Clonal Hematopoiesis Of Indeterminate Potential Mutations Research Articles

Differences in the mutational landscape of clonal hematopoiesis of indeterminate potential among races and between male and female patients with cancer

Clonal hematopoiesis of indeterminate potential (CHIP) has emerged as a significant precursor to hematological malignancies and is associated with several age-related diseases. We leveraged public data to explore differences in the mutational landscape of CHIP between males (Ms) and females (Fs) and across diverse racial populations. DNA (cytosine-5) methyltransferase 3 alpha (DNMT3A) mutations were substantially more prevalent in Fs than in Ms (38.94% vs. 31.37%, p-value: < 0.001, q-value: < 0.001). Additional sex combs-like 1 (ASXL1) mutations were more frequent in Ms than Fs (5.82% vs. 2.69%, p-value < 0.001, q-value < 0.001). In the racial cohorts with sufficient sample sizes, STAT5B and CSF1R mutations were most frequent in Asian populations (1.40% and 0.84%), followed by Black populations (0.98% and 0.24%) and White populations (0.29% and 0.09%) (p-value: < 0.001 , q-value: 0.023 for both genes). Several other CHIP mutations were enriched in Black: RARA, SMAD2, CDKN1B, CENPA, CTLA4, EIF1AX, ELF3, MSI1, MYC, SOX17, and AURKA. On the other hand, H3C1, H3C4, and MYCL were enriched in the Asian cohort. Our analysis highlights sex and racial differences in CHIP mutations among patients with cancer. As CHIP continues to gain recognition as a critical precursor to malignancies and other diseases, understanding how these differences contribute to CHIP's underlying mechanisms and clinical implications is critical.

Invasive Assessment of Coronary Artery Disease in Clonal Hematopoiesis of Indeterminate Potential.

Clonal hematopoiesis of indeterminate potential (CHIP) occurs due to acquired mutations in bone marrow progenitor cells. CHIP confers a 2-fold risk of atherosclerotic cardiovascular disease. However, there are limited data regarding specific cardiovascular phenotypes. The purpose of this study was to define the coronary artery disease phenotype of the CHIP population-based on coronary angiography. We recruited 1142 patients from the Vanderbilt University Medical Center cardiac catheterization laboratory and performed DNA sequencing to determine CHIP status. Multivariable logistic regression models and proportional odds models were used to assess the association between CHIP status and angiography phenotypes. We found that 18.4% of patients undergoing coronary angiography had a CHIP mutation. Those with CHIP had a higher risk of having obstructive left main (odds ratio, 2.44 [95% CI, 1.40-4.27]; P=0.0018) and left anterior descending (odds ratio, 1.59 [1.12-2.24]; P=0.0092) coronary artery disease compared with non-CHIP carriers. We additionally found that a specific CHIP mutation, ten eleven translocase 2 (TET2), has a larger effect size on left main stenosis compared with other CHIP mutations. This is the first invasive assessment of coronary artery disease in CHIP and offers a description of a specific atherosclerotic phenotype in CHIP wherein there is an increased risk of obstructive left main and left anterior descending artery stenosis, especially among TET2 mutation carriers. This serves as a basis for understanding enhanced morbidity and mortality in CHIP.

Clinical validation of Northstar Select, a novel liquid biopsy assay for comprehensive genomic profiling of solid tumors.

3072 Background: Comprehensive Genomic Profiling (CGP) liquid biopsy tests are vital tools for oncologists that enable the non-invasive detection of diverse somatic mutations, many of which correspond to targeted therapies, in circulating tumor DNA (ctDNA). However, these tests have less utility when ctDNA signal is low, which is common even in late-stage cancer patients. BillionToOne’s Northstar (NS) Select assay is a novel CGP test that seeks to leverage proprietary technology and novel calling algorithms to address this limitation by achieving higher sensitivity. Methods: Clinical samples for 182 unique patients with stage III or IV solid tumors were obtained via a prospective validation study assessing head-to-head concordance with widely adopted, commercially available ‘comparator’ liquid biopsy CGP assays. The study cohort was recruited from 1 large hospital center and 6 community clinics across the US and was diverse in patient demographics and clinical presentations. Over 15 different cancer types were represented in the cohort, with the majority of patients having either Lung, Breast, Colorectal, or Prostate cancer, all of which are commonly tested using liquid biopsies in the US. Pathogenic (including likely pathogenic) variants called by NS Select and/or the comparator assay were analyzed for concordance. For a subset of samples (N=28), white blood cell-derived genomic DNA was also processed to identify which variants were detected due to clonal hematopoiesis of indeterminate potential (CHIP). Results: In the head-to-head comparison, a large number of variants (N=380) were concordant between the two assays. In addition, NS Select detected 43% (N=147) more pathogenic variants than comparators when controlling for matched coverage regions. The majority of these variants were detected below the reported limit of detection of the comparator assays, but above the limit of detection of NS Select. The rate of CHIP mutations was not significantly different in the variants detected by NS Select (19.0% ± 7.6%) vs. comparators (17.2% ± 9.2%). Finally, the proportion of patients with no pathogenic variants detected was shown to be lower by 45% when using NS Select vs. the comparator assays (20/182 vs. 36/182). Conclusions: NS Select reported clinically useful information about the tumor for most patients. For patients in which ctDNA signal was high, NS Select had very high concordance with comparator tests. Furthermore, additional low-VAF pathogenic mutations identified by NS Select translated to a higher diagnostic yield compared to other CGP assays, and CHIP was ruled out as an explanation for these additional detections. This suggests that some patients with low levels of ctDNA would derive clinical benefit from testing with NS Select due to its high sensitivity.

Clonal hematopoiesis of indeterminate potential in patients with immunoglobulin light-chain AL amyloidosis

AbstractImmunoglobulin light-chain (AL) amyloidosis is characterized by the deposition of misfolded monoclonal free light chains, with cardiac complications accounting for patient mortality. Clonal hematopoiesis of indeterminate potential (CHIP) has been associated with worse cardiovascular outcomes in the general population. Its significance in AL amyloidosis remains unclear. We collected clinical information and outcome data on 76 patients with a diagnosis of AL amyloidosis who underwent deep targeted sequencing for myeloid neoplasia–associated mutations between April 2018 and August 2023. Variant allele frequency was set at 2% to call CHIP-associated mutations. CHIP mutations were present in patients with AL amyloidosis at a higher frequency compared with age-matched control individuals. Sixteen patients (21%) had at least 1 CHIP mutation. DNMT3A was the most frequent mutation (7/16; 44%). Compared with patients without CHIP, patients with CHIP had a higher prevalence of t(11;14) translocation (69% vs 25%, respectively; P = .004). Furthermore, among patients with renal involvement, those with CHIP had a lower Palladini renal stage (P = .001). At a median follow-up of 32.5 months, the presence of CHIP was not associated with worse overall survival or major organ dysfunction progression-free survival. Larger studies and longer follow-up are needed to better define the impact of CHIP in patients with AL amyloidosis.

Cost-Effective and Scalable Clonal Hematopoiesis Assay Provides Insight into Clonal Dynamics

Clonal hematopoiesis of indeterminate potential (CHIP) is a common age-related phenomenon that occurs when hematopoietic stem cells acquire mutations in a select set of genes commonly mutated in myeloid neoplasia which then expand clonally. Current sequencing assays to detect CHIP mutations are not optimized for the detection of these variants and can be cost-prohibitive when applied to large cohorts or serial sequencing. In this study, an affordable (∼$8 per sample), accurate, and scalable sequencing assay for CHIP is introduced and validated. The efficacy of the assay is demonstrated by identifying CHIP mutations in a cohort of 456 individuals with DNA collected at multiple timepoints in the Vanderbilt BioVU biobank and quantifying clonal expansion rates over time. A total of 101 individuals with CHIP/CCUS were identified, and individual-level clonal expansion rate was calculated using the variant allele fraction (VAF) at both timepoints. Differences in clonal expansion rate by driver gene were observed, but there was also significant individual-level heterogeneity, emphasizing the multifactorial nature of clonal expansion. Additionally, the study explores mutation co-occurrence and clonal competition between multiple driver mutations.

Solid Organ Transplant Recipients Exhibit More TET2-Mutant Clonal Hematopoiesis of Indeterminate Potential Not Driven by Increased Transplantation Risk.

Solid organ transplant recipients comprise a unique population of immunosuppressed patients with increased risk of malignancy, including hematologic neoplasms. Clonal hematopoiesis of indeterminate potential (CHIP) represents a known risk factor for hematologic malignancy and this study describes the prevalence and patterns of CHIP mutations across several types of solid organ transplants. We use two national biobank cohorts comprised of >650,000 participants with linked genomic and longitudinal phenotypic data to describe the features of CHIP across 2,610 individuals who received kidney, liver, heart, or lung allografts. We find individuals with an allograft before their biobank enrollment had an increased prevalence of TET2 mutations (OR, 1.90; P = 4.0e-4), but individuals who received transplants post-enrollment had a CHIP mutation spectrum similar to that of the general population, without enrichment of TET2. In addition, we do not observe an association between CHIP and risk of incident transplantation among the overall population (HR, 1.02; P = 0.91). And in an exploratory analysis, we do not find evidence for a strong association between CHIP and rates of transplant complications such as rejection or graft failure. These results demonstrate that recipients of solid organ transplants display a unique pattern of clonal hematopoiesis with enrichment of TET2 driver mutations, the causes of which remain unclear and are deserving of further study.

Abstract 3433: Characterization of co-occurring clonal hematopoiesis to identify high risk clones associated with hematologic cancer risk

Abstract Clonal hematopoiesis (CH) is the age-related clonal expansion of hematopoietic cells as a result of acquired mutations in driver genes, commonly referred to as clonal hematopoiesis of indeterminate potential (CHIP), or due to large-scale mosaic chromosomal alterations (mCAs). While the type and genomic location of CH exhibits varying associations with hematological parameters as well as lymphoid and myeloid malignancy risk, few studies have examined the co-occurrence of CH types. We characterized the frequency of co-occurring CH and examined the association of co-occurring CH with various cancer-related phenotypes to identify potential high-risk clones associated with hematologic cancer risk. We analyzed sequencing and genotyping array data from 453,807 participants in the UK Biobank to detect CHIP and mCAs. In total, 83,240 (18.3%) individuals had at least one detectable type of CH, with increasing age strongly associated with increasing frequency of CH (P &amp;lt; 2 × 10−16). The most common type of CH was mCAs (N= 67,081 (14.7%)), with mosaic loss of the Y (mLOY) and X (mLOX) chromosomes being most frequently observed in males and females, respectively. We noted inverse associations between mLOY or mLOX with autosomal mCAs, but positive associations between some autosomal mCAs (e.g., chr3 and chr18 mCAs). CHIP was detected in 20,354 (4.5%) individuals, with mutations in DNMT3A, TET2, and ASXL1 most common. Similar to mCAs, some forms of CHIP were inversely associated (e.g., DNMT3A CHIP with most other CHIP mutations) while others displayed positive associations (e.g., JAK2 CHIP with NFE2 CHIP), suggesting both instances of mutual exclusivity as well as cooperation. We likewise noted several instances of CHIP and mCAs co-occurring (e.g., MYD88 and chr18 mCAs) and overlapping (e.g., JAK2 and 9p24 mCAs) more frequently than expected. Compared to those with no CH, participants with CH had notable alterations in blood cell counts, leukocyte telomere length (LTL), and elevated hematologic cancer risk even after adjusting for age, sex, smoking, and genetic ancestry. Furthermore, co-occurring CH had more pronounced associations, with the greatest alterations and hematologic cancer risk generally noted in participants with overlapping CHIP and mCAs (e.g., MYD88 and 3p22 mCAs). These findings highlight substantial enrichment in CH co-occurrences, particularly in the positional overlap of CHIP and mCAs, and indicate an increased risk of hematological malignancies when CH types overlap (HR = 29.5, 95% CI [24.0, 36.3], P &amp;lt; 2 × 10−16). Overall, this study details the landscape of co-occurring CH and nominates high risk co-occurrences with strong implications for future hematological malignancy risk. Citation Format: Kara M. Barnao, Aubrey K. Hubbard, Weiyin Zhou, Irenaeus Chan, Duc Tran, Yin Cao, Stephen J. Chanock, Kelly L. Bolton, Mitchell J. Machiela. Characterization of co-occurring clonal hematopoiesis to identify high risk clones associated with hematologic cancer risk [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3433.

Abstract 790: Sex and race-dependent variations in the mutational landscape of clonal hematopoiesis

Abstract Introduction: Clonal hematopoiesis of indeterminate potential (CHIP) has emerged as a significant precursor to hematological malignancies and is associated with several age-related diseases. Recent studies in relatively small disease specific cohorts have suggested that CHIP may exhibit variations among different races and between males and females raising intriguing questions about potential genetic and environmental influences. Understanding the differences in CHIP across races and between males and females may have implications for personalized cancer risk assessment and targeted therapeutic strategies. Methods: Patient’s data were obtained from the Cancer Therapy and Clonal hematopoiesis via cBioportal. The original study was designed to examine clonal hematopoiesis mutations that were found in blood samples obtained from 24,146 patients with non-hematological cancers and their tumor-blood pairs were analyzed using targeting sequencing data MSK-IMPACT (Memorial Sloan Kettering-IMPACT). The cohort consisted of 45.7% males and 54.3% females; including 6.8% Asians, 6.2% Blacks, and 76.3% Whites. We examined mutation frequencies among these racial groups and between genders, employing the two-sided Fisher's exact test and adjusting p-values for multiple comparisons. Differences were considered significant when both P value and Q values are less than 0.05. Results: DNMT3A mutations were substantially more prevalent in females than in males (38.94% vs 31.37%, p-value: &amp;lt;10−10, q-value: 6.19e−09), While ASXL1 mutations were more frequent in males than females (5.82% vs 2.69%, p-value: &amp;lt;10−10, q-value: 6.19e−09). In the racial cohorts with sufficient sample sizes, STAT5B and CSF1R mutations were most frequent in Asian (1.40% and 0.84%), followed by Black (0.98% and 0.24%) and White populations (0.29% and 0.09%), (p-value: 8.099e−04 and 7.490e−04, q-value: 0.0234 and 0.0232). Several other CHIP mutations were enriched in Black: RARA, SMAD2, CDKN1B, CENPA, CTLA4, EIF1AX, ELF3, MSI1, MYC, SOX17, AURKA. On the other hand, H3C1, H3C4, MYCL were enriched in the Asian cohort. Conclusion: Our analysis provides insights into the complex interplay of sex and racial factors in shaping CHIP mutation frequencies. As CHIP continues to gain recognition as a critical precursor to malignancies, understanding these variations contributes to refining our understanding of its underlying mechanisms and clinical implications. Citation Format: Kanaka Dhuri, Houda Alachkar. Sex and race-dependent variations in the mutational landscape of clonal hematopoiesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 790.

Abstract 6407: Identification of novel chemotherapy-related CHIP variations in patients with high-grade serous ovarian cancer

Abstract Background: Hematopoietic lineage differentiation is subjected to genetic mutations that, due to fitness advantages, might give rise to clonally expanded populations. Clonal hematopoiesis of indeterminate potential (CHIP) is defined as the outgrowth of a single clone driven by acquired somatic mutations in hematopoietic stem cells (HSCs), in the absence of hematological abnormalities. Previous studies have shown the association of CH with aging and a higher risk of developing secondary hematologic malignancies in cancer patients treated with chemotherapy agents. It is therefore of great interest to study CH incidence prior to and post chemotherapy exposure and its association with the evolution of hematologic malignancies. We aimed to characterize CHIP variants of a highly selected group of patients with high-grade serous ovarian cancer (HGSC) who underwent neoadjuvant chemotherapy (NACT). Methods: Comprehensive ultra-high-depth whole exome sequencing, employing unique molecular barcode technologies, was performed using plasma-derived cell-free DNA (cfDNA) and matched white blood cells (WBC) DNA and tumor DNA from pre-NACT (n=10) and post-NACT (n=10) samples of patients with HGSC. CHIP variants were defined as heterozygous variants found in both the WBC and cfDNA samples from the same patients with variant allele frequency less than 5% in the WBC and higher than 0.5% in cfDNA samples. Results: Our analysis identified 93,088 variants, impacting 13,780 genes. Among them, 463 variants were already known and published, and 5,548 variants were common to the COSMIC genes signature. The number of CHIP variants significantly decreased after chemotherapy (p = 0.004). We then focused on CHIP variants enriched after chemotherapy and identified 77 that showed higher VAF in post-NACT cfDNA samples, which may be associated with the development of therapy-related acute myeloid leukemia/myelodysplastic syndrome (t-AML/MDS). Among them, interestingly, we found a missense mutation with protein change in CDK12 (chr17_39492765_G_T). We noticed that 38% of the CHIP variants found in cfDNA samples, were also found in matched tumor samples. Among these, another CDK12 missense mutation (chr17_39492768_A_T) showed higher VAF in post-NACT tumors. Conclusions: Our innovative approach detected a higher number of CHIP variants than currently characterized. Analysis of cfDNA from HGSC patients consistently demonstrated a reduction in CHIP mutations post-NACT. The subset of variants with increased VAF post-NACT may be associated with therapy-related t-AML/MDS. The detection of cfDNA CHIP variants in matched tumors highlights the potential predictive role of CHIP in t-AML/MDS development, emphasizing its consideration in therapeutic protocols. Citation Format: Sara Corvigno, Amma Asare, Jun Yao, Li Zhao, Nicole Fleming, Joseph Celestino, Richard A. Hajek, Ency A. Arboleda Goette, Ridge T. Rogers, Tri V. Nguyen, Raymond N. Montoya, Karen H. Lu, Amir A. Jazaeri, Shannon N. Westin, Anil K. Sood, Sanghoon Lee. Identification of novel chemotherapy-related CHIP variations in patients with high-grade serous ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6407.

Heart and blood: clonal hematopoiesis

Cardiovascular diseases are among the leading causes of death worldwide, with well-known modifiable risk factors, such as smoking, overweight, lipid metabolism disorders, lack of physical activity and high blood pressure playing asignificant role. Recent studies have now identified "clonal hematopoiesis" as anovel blood-based risk factor. Clonal hematopoiesis arises from mutations in hematopoietic stem cells, which lead to the expansion of mutated blood cells. Mutated cell clones can be detected in over 40% of individuals over 50years old, with more than 15% of those over 90years old harboring large clones. Surprisingly, mutated cells predispose to the development of leukemia only to a minor extent, leading to the term clonal hematopoiesis of indeterminate potential (CHIP); however, it has been shown that CHIP is associated with an increased risk of cardiovascular diseases. Individuals with CHIP-associated gene mutations have an elevated risk of atherosclerotic vascular diseases, stroke and thrombosis. Patients with heart failure with reduced ejection fraction (HFrEF), whether of ischemic or non-ischemic origin and patients with heart failure with preserved ejection fraction (HFpEF) exhibit an increased number of mutated cells in the blood. The presence of CHIP mutations is linked to apoorer prognosis in patients with existing cardiovascular diseases. Future research should aim at a better understanding of the specific effects of different mutations, clone sizes and combinations to develop personalized therapeutic approaches. Various anti-inflammatory therapeutic drugs are available, which can be tested in controlled studies.

Somatic and Germline Variants and Coronary Heart Disease in a Chinese Population

The genetic basis of coronary heart disease (CHD) has expanded from a germline to somatic genome, including clonal hematopoiesis of indeterminate potential (CHIP). How CHIP confers CHD risk in East Asian individuals, especially those with small clones (variant allele fraction [VAF] 0.5%-2%) and different genetic backgrounds, was completely unknown. To investigate the CHIP profile in a general Chinese cohort by deep sequencing and further explore the association between CHIP and incident CHD considering germline predisposition. This cohort study used data from 3 prospective cohorts in the project Prediction for Atherosclerotic Cardiovascular Disease Risk in China. Participants without cardiovascular disease or cancer at baseline were enrolled in 2001 and 2008 and had a median follow-up of 12.17 years extending into 2021. CHIP mutations were detected by targeted sequencing (mean depth, 916×). A predefined CHD polygenic risk score (PRS) comprising 531 variants was used to evaluate germline predisposition. The main outcome was first incident CHD. Among 6181 participants, the median (IQR) age was 53.83 years (45.35-62.39 years); 3082 participants (49.9%) were female, and 3099 (50.1%) were male. A total of 1100 individuals (17.80%) harbored 1372 CHIP mutations at baseline. CHIP was independently associated with incident CHD (hazard ratio [HR], 1.42; 95% CI, 1.18-1.72; P = 2.82 × 10-4) and presented a risk gradient with increasing VAF (P = 3.98 × 10-3 for trend). Notably, individuals with small clones, nearly half of CHIP carriers, also demonstrated a higher CHD risk compared with non-CHIP carriers (HR, 1.33; 95% CI, 1.02-1.74; P = .03) and were 4 years younger than those with VAF of 2% or greater (median age, 58.52 vs 62.70 years). Heightened CHD risk was not observed among CHIP carriers with low PRS (HR, 1.02; 95% CI, 0.64-1.64; P = .92), while high PRS and CHIP jointly contributed a 2.23-fold increase in risk (95% CI, 1.51-3.29; P = 6.29 × 10-5) compared with non-CHIP carriers with low PRS. Interestingly, the diversity in CHIP-related CHD risk within each PRS group was substantially diminished when removing variants in the inflammatory pathway from the PRS. This study revealed that elevated CHD risk attributed to CHIP was nonnegligible even for small clones. Inflammation genes involved in CHD could aggravate or abrogate CHIP-related CHD risk.

The Impact of Clonal Hematopoiesis on Clinical Outcomes and Clonal Dynamics in Older Lymphoma Patients Receiving Chemotherapy

Background: CHIP is more commonly encountered in cancer patients, such as those with lymphoma, than in the general population likely attributable to age, cancer risk factors and treatment. While the adverse health associations with clonal hematopoiesis of indeterminate potential (CHIP) are established, its impact on the immediate tolerability of chemotherapy and longer-term blood count reconstitution are unknown. Also, while it is known that certain CHIP drivers, especially those affecting DNA damage responses, may be selected during cancer treatment, comprehensive studies of CHIP clonal dynamics along the course of treatment are lacking. We hypothesized that CHIP may be a risk factor for chemotherapy complications in older lymphoma patients related to dysfunctional bone marrow and blood cells. Our Aims were to ascertain CHIP status using targeted sequencing, investigate the influence of CHIP on adverse events during chemotherapy, and the changes in clonal dynamics. Methods: We evaluated the prevalence, associations, clonal dynamics and impact of CHIP on treatment toxicity and blood count recovery in lymphoma patients aged &amp;gt; 60 undergoing 1 st or second line cytotoxic chemotherapy. CHIP (Ion torrent NGS, 53 genes including coverage for DNA damage response (DDR) mutations: TP53, PPM1D, CHEK2 and SRCAP was performed on peripheral blood (PB) samples at baseline, after 3 chemotherapy cycles, at 6 and 12 months post chemotherapy. Ion Torrent VAF cutoff was 2%. Integrated genomics viewer (IGV) was used to detect known variants at &amp;lt; 2% VAF. We compared blood count parameters and treatment complications between those with and without CHIP overall or DDR mutations in particular. Results: 78 of planned 180 patients are available for analysis and 74 with non-lymphoma-related mutations are included. Median age was 70, 58% female. 61% had DLBCL and 19% follicular lymphoma. 88% received first line chemotherapy (68% anthracycline containing) and 15% had received radiation in the past. With a median follow up of 19 months, 82% remain alive. All CHIP (and DDR) mutations were detected in 27% (1.4%) patients at baseline, in 33.3% (5.3%) after cycle 3, in 47.2% (27.8%) at 6 months and 38.7% (22.6%) 12 months post chemotherapy respectively (Figure 1). IGV inspection and deep sequencing confirmed that most DDR variants were present at &amp;lt;2% VAF at baseline and expanded with treatment. Moreover, DDR CHIP peaked at the 6 months post-chemotherapy timepoint, with contraction in overall prevalence and VAF by 12 months. In contrast, most non-DDR mutations remained stable or increased slightly. The clonal dynamics of CHIP and DDR mutations are visible in Figure 2. Comparing those, with or without baseline or acquired CHIP or DDR mutations, there were no significant differences in most baseline clinical and laboratory characteristics, chemotherapy dose delays or reductions. In particular, MCV and RDW did not differ at baseline or increase preferentially in those with or without mutations. However, patients with DDR mutations had higher eosinophil counts at baseline (0.2 versus 0.1, p=.01), higher eosinophil counts over time (p=.0003), were more likely to visit an emergency department (86% versus 52%, p=.03), and sustain infections on treatment (43% versus 20% p=.07). A higher percentage of patients with DDR mutations had monocyte counts that exceeded normal reference ranges 6 months post (23% versus 10%, p=.01) and (trend) 12 months post (30% versus 12.9%, p=0.3). More patients with CHIP had marginal zone lymphoma (21% versus 2.5%, p=.04), experienced fewer neurologic toxicities (22% versus 52%, p=.006) but more respiratory infections (19.4% versus 2.3%, p=.02). The monocytes of patients with CHIP (compared without) surpassed baseline monocyte counts at 6 months (57.1% versus 16%, p=.004), and 12 months (52.3% versus 20%, p=0.03) and exceeded normal reference range (21% versus 4%, p=.04) at 6 months. Conclusion: The prevalence of CHIP is high in older lymphoma patients, with preferential expansion of clones harboring DDR mutations during treatment. Most of these DDR variants would fall below routine clinical NGS reporting thresholds if sampled at baseline, or after post-therapy contraction. DDR CHIP and CHIP overall associate with different complication rates on chemotherapy and both associate with post-treatment monocytosis. These novel DDR CHIP immune alterations warrant further mechanistic study.

Unlocking the Role of Endothelial MPL Receptor and JAK2V617F Mutation: Insights into Cardiovascular Dysfunction in MPNs and Chip

Introduction Patients with JAK2V617F-positive myeloproliferative neoplasms (MPNs) and clonal hematopoiesis of indeterminate potential (CHIP) are at a significantly higher risk of cardiovascular diseases (CVDs). Vascular endothelial cells (ECs) carrying the JAK2V617F mutation can be detected in many MPN patients. The thrombopoietin receptor MPL is expressed on vascular ECs, though its role in endothelial function is unclear. In this study, we investigated the mechanisms through which the JAK2V617F mutation induces endothelial dysfunction to accelerate CVDs, shedding light on endothelial MPL as a potential therapeutic target for preventing or mitigating cardiovascular complications in JAK2V617F-positive MPNs. Methods JAK2V617F Flip-Flop mice (FF1; provided by Dr. Radek Skoda) were crossed with VEcadherin-creERT2 mice (CDH5) to generate CDH5 +/-FF1 +/- mice, which can be induced by tamoxifen to express human JAK2V617F specifically in vascular ECs but not in blood cells. MPL fl mice (provided by Dr. Warren Alexander) were crossed with CDH5 +FF1 + mice to generate CDH5 +FF1 +MPL fl/fl mice. To validate findings in transgenic murine models in human cells, we utilized a pair of isogenic induced pluripotent stem (iPS) cell lines derived from the same MPN patient, one carrying the JAK2V617F mutation (PVB1.4) and the other being JAK2 wild-type (PVB1.11). These iPS cell lines were differentiated into human ECs using a modified iPS differentiation protocol. Results CDH5 +FF1 + mice exhibited mild thrombocytosis but no cardiac dysfunction. However, when challenged with a high-fat diet, these mice developed dilated cardiomyopathy with significant decreases in LV ejection fraction and increases in LV end-diastolic and end-systolic volumes. Pathological evaluation revealed the presence of thromboses in segment pulmonary arteries and scattered coronary capillaries. There was intimal thickening, smooth muscle cell thickening, and perivascular fibrosis of scattered coronary arterioles in CDH5 +FF1 + mice compared to control mice. These findings, along with impaired cardiac EC function (measured by angiogenesis in vitro) and loss of EC markers, as well as significant enrichment of gene expression signatures associated with inflammatory response and epithelial-mesenchymal transition in JAK2V617F mutant cardiac ECs, suggest that the JAK2V617F mutation induces endothelial-to-mesenchymal transition (EndMT) in cardiac ECs from the CDH5 +FF1 + mice. Similarly, JAK2 wild-type ECs derived from PVB1.11 iPS cell line maintained the expression of EC markers and the characteristic cobblestone endothelial morphology throughout serial passages in vitro; in contrast, JAK2V617F mutant ECs derived from PVB1.4 exhibited a gradual loss of EC marker expression, decreased EC function, and underwent a phenotypical transition toward a fibroblastoid morphology, providing compelling evidence of EndMT induction by the JAK2V617F mutation in human ECs. We noticed that the thrombopoietin receptor MPL is abundantly expressed in the heart's vascular endothelium, compared to other tissues (e.g., lung, marrow, spleen). MPL expression is upregulated in JAK2V617F mutant ECs compared to wild-type ECs, and Inhibiting JAK-STAT signaling using Ruxolitinib abolished this MPL upregulation. To investigate the role of endothelial TPO/MPL signaling in JAK2V617F-induced cardiovascular dysfunction, we generated CDH5 +FF1 +MPL fl/fl mice to knock down MPL in JAK2V617F-bearing vascular ECs. The CDH5 +FF1 +MPL fl/fl mice maintained normal blood counts and cardiac function even after a high-fat diet challenge. In JAK2V617F mutant human ECs derived from PVB1.4 iPS cell line, treatment with AMM2, an anti-MPL neutralizing antibody, preserved EC markers and endothelial morphology compared to untreated mutant ECs. These results demonstrated that inhibiting the endothelial MPL can suppress JAK2V617F-induced EndMT and prevent cardiovascular dysfunction caused by mutant ECs. Notably, the endothelial MPL receptor is not indispensable for the normal physiological regulation of blood cell counts and cardiac function. Conclusion Our study provides valuable insights into the increased risk of CVDs observed in patients with JAK2V617F-positive CHIP and MPNs. Further investigations into the role of EndMT in other CHIP-associated mutations may shed light on the diverse CVD risks associated with different CHIP mutations.

Role and Prevalence of Risk Factors That Trigger Therapy Related Myeloid Neoplasms (TRMN) in Patients with Previous Treated Breast Cancer

INTRODUCTION: Cytotoxic treatment of a primary tumor (PT) is one of the main drivers for the development of a Therapy Related Myeloid Neoplasm (TRMN). However, other intrinsic factors associated with TRMN contribute to their heterogeneous etiology. It has been suggested that around 18.5% of TRMN patients have a germline cancer mutation. On the other hand, prevalence of pre-existing clonal hematopoiesis of indeterminate potential (CHIP) is estimated in around 30% at the time of PT diagnosis, which has been associated with a worse outcome and a higher incidence of TRMN. Thus, scenarios with different etiologies must be identified for TRMN classification, differential diagnosis, and management of patients at risk. AIM: To evaluate the relative risk factor contribution of CHIP and germline mutations to develop TRMN in patients with previous breast cancer (BC) treated with chemotherapy and/or radiotherapy. METHODOLOGY: Paired samples from bone marrow (BM) and peripheral blood (PB) of 19 TRMN patients with a previous BC have been studied by tNGS (N=7) and WES (N=12) at the time of TRMN diagnosis to describe the molecular alterations (including germline landscape and somatic drivers). BM samples were used as a source of tumoral DNA, while CD3+ T lymphocytes were isolated from PB and were used as germline sample. Variants with frequency (VAF)&amp;lt;30% found in BM but not in CD3+ sample were annotated as somatic. Variants with 2%&amp;gt;VAF&amp;lt;10% found in PB of BC patients were annotated as CHIP. Only pathogenic/likely pathogenic variants were considered. RESULTS: Germline mutations in cancer predisposition genes and myeloid genes were found in 31.3% and 62.5% of TRMN patients, respectively. Myeloid somatic mutations were found in 37.5.1% of TRMN patients (Table 1). On the other hand, CHIP prevalence in longitudinal samples of BC series was found in 27.3% and 45.5% of treatment-naïve and 6-12 months after the treatment samples, respectively. The somatic alterations found in TRMN patients were compared with CHIP in sequential blood samples of 25 BC patients. Three somatic profiles were observed (Fig.1): A) Drivers of TRMN not found in any of the BC samples might highlight that both neoplasms do not share risk factors but might involve independent germline predisposition instead. B) TRMN drivers not found in pretreatment samples but appearing in BC samples after cytotoxic therapy suggest a prominent role of treatment. C) TRMN drivers found at low frequency in the BC samples prior to the treatment might suggest that other factors different than cytotoxic therapy could be involved in TRMN development. Similar percentage of somatic drivers in TRMN patients was found in the three profiles; however, different gene frequencies were observed. Finally, CHIP and TRMN drivers were also evaluated regarding the germline predisposition landscape. The percentage of patients with CHIP was higher in patients with no germline cancer predisposition mutations. However, a higher increase after cytotoxic treatment was observed in patients with germline predisposition (Table 1). On the other hand, TRMN patients with no germline cancer predisposition showed an increased percentage of myeloid somatic drivers (25%) in comparison with germline mutation carriers (13%). Otherwise, 37.5% of TRMN patients were carrying germline mutations in cancer predisposition and myeloid genes, suggesting low relevance of treatment in these patients. CONCLUSION: Our results identified different etiologic scenarios in TRMN, highlighting the role of germline landscape instead of treatment. Otherwise, the percentage of somatic drivers in TRMN patients was found increased in patients with no germline cancer mutations. However, CHIP differences in pre and post treatment samples were found to be higher in BC patients with germline mutations. Deeper studies regarding the involved genes and somatic and germline associations comparing different treatment regimens are ongoing and will be further presented to discuss the contribution of different risk factors to the development of TRMN in BC patients. Understanding the risk factors contribution to TRMN development is needed for the adequate management of BC patients. Financial support: This work was supported by a grant from the Instituto de Salud Carlos III, Ministerio de Economia y Competitividad, Spain (PI 20/00531)(Co-funded by European Regional Development Fund. ERDF, a way to build Europe) and Fundació Adey.

Allogeneic Hematopoietic Cell Transplant Recipients Carrying DNMT3A and ASXL1 Mutations More Frequently Develop Severe Graft Versus Host Disease and Arterial Hypertension

Background: Clonal hematopoiesis of indeterminate potential (CHIP) is defined as the presence of an expanded blood-cell clone due to acquired somatic mutations in hematopoietic stem cells without evidence of hematologic malignancy, dysplasia or cytopenia. CHIP associates with an increased risk of hematologic malignancies, as well as a pro-inflammatory state and an increased risk for cardiovascular disease. Inflammation furthermore plays crucial roles in the pathogenesis of arterial hypertension (aHTN), which we thus hypothesized may be also induced by CHIP. The epigenetic regulators DNMT3a and ASXL1 count to the most commonly mutated genes in CHIP. While donor CHIP mutations were previously associated with an increased risk for acute Graft versus Host Disease (GVHD), we here report that patients with DNMT3A or ASXL1 mutations in pre-transplant samples also show an enhanced risk for the development of severe (stadium III/IV and systemically treated) GvHD as well as arterial hypertension (aHTN). Methods: We retrospectively analyzed a cohort of 129 patients with myeloid malignancies (74 AML, 25 MDS, 5 CMML, 25 MPN) treated with allo-HCT at our University Hospital between January 2020 and April 2023. Next generation sequencing data performed on bone marrow samples collected maximum one month prior to allo-HCT were analyzed and correlated with the prevalence of pre-transplant diagnosed aHTN (n=129 analyzed patients) and the development of post-transplant GvHD at 3 months post-allo-HCT (n=108 analyzed patients). Results: DNMT3A and/or ASXL1 mutations were surprisingly common and detected in 78/129 patients (61%), (DNMT3A-mutations: 42/129, 33%; ASXL1-mutations: 44/129 (34%); double mutations: 8/129, 6%). Patients with pre-transplant detectable DNMT3A/ASXL1 mutations in the bone marrow showed an increased risk to develop GvHD within 3 months post-transplant and more frequently showed severe GvHD (28/61, 46%) vs. patients with no detectable DNMT3A or ASXL1 mutations (overall GvHD: 34/61, 56% vs. 16/47, 34%, p&amp;lt;0.05; severe GvHD: 28/61, 46% vs. 12/47, 25.5%, p&amp;lt;0.05). Broken down to single mutations: DNMT3A mutation carriers showed a tendency for increased overall GvHD incidence when compared to patients with no detectable DNMT3A or ASXL1 mutations (19/35, 54,3%, versus 12/47, 25.5%, p=0.07), whereas ASXL1 mutation carriers showed significantly higher overall GvHD incidence compared to patients with no detectable DNMT3A or ASXL1 mutations (19/32, 59,4%, vs. 16/47, 34% , p&amp;lt;0.05). The frequency of severe GvHD was significantly higher in both DNMT3A (17/35, 48.6%, p&amp;lt;0.05) and ASXL1 mutation carriers (16/32, 50%, p&amp;lt;0.05) when compared to patients with no detectable DNMT3A or ASXL1 mutations(12/47, 25.5%). DNMT3A/ASXL1-mutation carriers had more frequently arterial hypertension compared to patients with no detectable DNMT3A or ASXL1 mutations(54/78, 69% vs. 22/51, 43%, p&amp;lt;0.05). DNMT3A mutation carriers showed in 28/42 (66.7%) of cases aHTN, whereas ASXL1 mutation carriers showed in 32/44 (72.7%) of cases aHTN, and thus in both categories significantly (p&amp;lt;0.05) higher aHTN rates compared to patients with no detectable DNMT3A or ASXL1 mutations (22/51, 43% with aHT). The presence of DNMT3A/ASXL1 mutations did not delay the time to the engraftment of neutrophils (25.1 vs. 20.5 days in DNMT3A/ASXL1 carriers compared to patients with no detectable DNMT3A or ASXL1 mutations, p=0.64) or thrombocytes (25.6 days vs. 22.6 days, p=0.89). Interestingly, the relapse rates were by trend lower in DNMT3A/ASXL1 carriers when compared to patients with no detectable DNMT3A or ASXL1 mutations in the pre-transplant bone marrow sample (19,1% vs. 28%, p=0.33), although higher numbers of patients need to be analyzed to ensure whether these effects are significant. Conclusion: ASXL1 and DNMT3A mutations are commonly documented in patients with myeloid malignancies undergoing allo-HCT, and associate with increased rates of severe acute GvHD and pre-transplant arterial hypertension, but perhaps with lower relapse probability in the post-transplant setting. The biologic mechanisms underlying these observations are under further investigation. An extended follow-up of these patients shall be presented at the meeting.

Branching Trajectories and Diversification of Clonal Escape in Aplastic Anemia Revealed By Single-Cell Genomics

Acquired aplastic anemia (AA) is a bone marrow failure resulting from an autoimmune T-cell attack against hematopoietic stem and progenitor cells (HSPCs). Several escape mechanisms within the HSPC compartment have been reported: i) adaptive alterations causing loss of high-risk HLA allele of AA development [deletion or uniparental disomy (UPD) of chromosome 6p including HLA cluster region, and loss-of-function (LOF) mutations in HLA gene], ii) clonal expansion of paroxysmal nocturnal hemoglobinuria (PNH) clone resulting from PIGA mutation, and iii) presence of clonal hematopoiesis of indeterminate potential (CHIP) mutations (i.e., BCOR/ BCORL1, DNMT3A, ASXL1). Multiple types of alterations often co-occur, however due to the inherent limitations of conventional methods, it is not known if i) these alterations are in the same or independent clones, ii) what is the mutational hierarchy, and iii) what is the cell of origin. We addressed these questions using single-cell and bulk genomic sequencing. We developed custom single-cell panels covering HLA class I and II genes, along with 14 genes commonly mutated in AA and myelodysplastic syndromes. To identify copy number variations and UPD, we included 197 single nucleotide variants (SNVs) frequent across all ethnic backgrounds on chromosomes 6, 7, 8, 20, and 21. The TotalSeq™-D panel (BioLegend), was included to target 42 surface antigens and the samples were prepared on the Tapestri platform (Missionbio). High-resolution HLA genotyping was done using AlloSeq Tx 17 hybrid capture NGS assay (CareDx), and for confirmatory bulk sequencing we applied a custom duplex UMI NGS panel (TWIST Bioscience). We examined ten patients with severe AA (pediatric: n=6, age range 2-15 years; adult: n=4, 26-67), seven patients with refractory cytopenia of childhood (RCC, age range 2-16 years), who presented a hypocellular marrow and absence of a genetic predisposition syndrome, and one healthy control. All 17 patients had at least one of the HLA-A or HLA-B risk alleles linked to AA development. A total of 136,505 cells (median 4,467/run) were successfully genotyped across the samples. Single-cell trajectory analysis revealed that all identified clones arose independent of each other (Figure 1). UPD6p clones were found in five patients with three having multiple UPD6p clones carrying different breakpoints, pointing to clonal diversification. Additionally, three cases had LOF mutations in HLA-A or HLA-B (two having coexisting UPD6p). In a patient with two UPD6p and two HLA-A mutant clones, we verified that HLA-A risk allele (A*02:01) was lost in each instance. Multi-omic analysis revealed that these clones had both granulocytic and non-granulocytic (incl. lymphocytic) surface phenotypes, suggesting their early origin within hematopoietic ontogeny. Seven patients had nine independent clones with PIGA mutations (0.3-11.3% of the cells), consistent with its tendency to generate clonal mosaicism. Clones with mutations in BCOR/BCORL1, ASXL1, DNMT3A, and TET2 were identified in six, seven, four, and two patients, respectively. We next analyzed how many patients carry multiple clones and found that 65% (11/17) have concomitant clones, with the majority (9/11) belonging to different types of clonal escape (Figure 1). Finally, we found that 4/6 patients with adaptive HLA loss (representing true clonal escape from T-cell autoimmunity) also carried CHIP clones, indicating that adaptive hematopoiesis does not protect from the acquisition of CHIP mutations. In conclusion, we show that patients with AA across age spectrum and some patients with RCC share similar clonal backgrounds, with multiple functionally redundant alterations arising independently from coexisting CHIP clones. For the first time at a single-cell level, we were able to resolve the multifaceted clonal mosaic generated by the immunological forces at play in AA, and precisely unravel their immunoediting consequences.

Clonal hematopoiesis of indeterminate potential in atrial fibrillation: prevalence and an association with progression

Abstract Background Both clonal hematopoiesis of indeterminate potential (CHIP) and atrial fibrillation (AF) are age-related conditions. Also, CHIP is associated with an increased risk of cardiovascular disease which might contribute to the development of AF. However, the direct association between CHIP and AF is unknown. Objective To evaluate the potential role of CHIP in the development and progression of AF. Methods Deep-targeted sequencing of 24 CHIP mutations was performed in 1,004 patients with AF and 3,341 non-AF healthy adults. Variant allele fraction (VAF) ≥2.0% indicated the presence of CHIP mutations. The association between CHIP and AF was evaluated by the comparison of (1) the prevalence of CHIP mutations between AF and non-AF adults and (2) clinical characteristics discriminated by CHIP mutations within AF patients. Results The mean age was 67.6 ± 6.9 vs. 58.5 ± 6.5 years in AF (paroxysmal, 39.0%; persistent, 61.0%) and non-AF cohorts, respectively. Twenty-four CHIP mutations with a VAF of at least 0.02 were found in 237 (23.6%) AF patients and 356 (10.7%) non-AF adults (p&amp;lt;0.001). The most common CHIP mutation genes in AF were DNMT3A (13.5%), TET2 (6.6%), and ASXL1 (1.5%). After multivariable adjustment, detected CHIP mutations were 1.4-fold higher in AF patients than in non-AF adults [odds ratio (OR), 1.38 and 95% confidence interval (CI), 1.10-1.73, p&amp;lt;0.01 for all AF; OR (95% CI), 1.50 (1.14-1.99), p&amp;lt;0.01 for long-standing persistent AF]. In gene-specific analyses, TET2 somatic mutation presented the highest association with AF (OR, 1.63; 95% CI, 1.03–2.56, p=0.036). AF patients with CHIP mutations were older and had more diabetes, a longer AF duration, and a higher E/E’ than those without CHIP mutations (all p&amp;lt;0.05). Conclusion CHIP mutations, primarily DNMT3A or TET2, are 1.4-fold more prevalent in AF than non-AF adults and might contribute to the progression of AF. Further studies are required to elucidate the underlying pathophysiologic role of CHIP in AF.

Abstract 15748: Association of Clonal Hematopoiesis in the Setting of Human Immunodeficiency Virus Infection With Subclinical Atherosclerosis and Vascular Inflammation

Background: Clonal hematopoiesis of indeterminate potential (CHIP) is associated with cardiovascular disease (CVD) and common in HIV, but whether CHIP contributes to atherosclerosis in HIV is unknown. We hypothesized CHIP is associated with atherosclerosis and arterial inflammation among people with HIV (PWH). Methods: We studied treated, suppressed PWH ages 35-70 years old with ≥1 CVD risk factor. CHIP mutations were detected with a validated targeted sequencing assay. We measured carotid intima-media thickness (IMT) longitudinally with ultrasound and aortic inflammation and lymph node activity using cross-sectional 18 F-FDG-PET. Inflammatory biomarkers were measured with a multiplex electrochemiluminescence assay. We used linear regression with adjustment for age, sex, nadir CD4 count, smoking, hypertension, diabetes, and hyperlipidemia. Results: We included 231 PWH (52±9 years, 7% female). 32 (14%) had CHIP with median variant allele fraction of 3.1%. Common mutations were in DNM3TA (n=21) and TET2 (n=6). Only age was associated with CHIP (OR 2.3 per decade older, 95%CI 1.2-3.9; p=0.003). Among N=165 (CHIP=22), mean IMT was 1.0 mm with and without CHIP (p=0.63), unchanged after adjustment (Figure). CHIP was not associated with prevalent or incident plaque. Over 3.2 years, IMT progression was faster among those with CHIP (0.033 mm/year; p=0.10), attenuated after adjustment (0.022 mm/year; p=0.27). Among 80 with FDG-PET, CHIP (n=12) was associated with higher lymph node activity (SUV p=0.04) that was attenuated in reference to background activity and adjusted for risk factors. CHIP was not associated with arterial inflammation (p=0.83), inflammatory markers, or viral persistence markers. Conclusions: Among PWH, CHIP mutations were not associated with subclinical atherosclerosis or arterial inflammation, proposed mechanisms of how CHIP could cause CVD. Clinical outcomes studies are needed to ascertain the impact of CHIP on CVD in HIV.

Abstract 15784: Clonal Hematopoiesis of Indeterminate Potential is Associated With Increased Risk of Incident Hypertension

Introduction: Clonal hematopoiesis of indeterminate potential (CHIP) is associated with an increased risk of heart failure (HF) and stroke, particularly HF with preserved ejection fraction and hemorrhagic stroke (HS). Hypothesis: We hypothesized that CHIP is associated with incident hypertension and this association mediates the effect of CHIP on HF and HS. Methods: In 200K UK-Biobank participants with exome sequencing, we ascertained CHIP as variant allele fraction (VAF) ≥2% and large CHIP as VAF ≥10%. Hypertension, HF, and HS diagnosis were determined based on the ICD-9 and ICD-10 codes. Cox proportional hazards models were used to test the association of both CHIP and the CHIP subtypes based on the most implicated driver genes (i.e., DNMT3A , TET2 , and ASXL1 ) with incident hypertension. Logistic regression models were used for mediation analyses, quantifying the extent to which hypertension mediates the effects of CHIP. Results: After excluding those with hematological malignancy (n=1,025) and pre-existing hypertension (n=14,754), 184,760 participants (56.14±8.12 years, 44.25% male, and 95.33% white ethnicity) were included. During a median follow-up of 12.2 years, 42,049 (22.76%) participants developed hypertension. CHIP mutations were significantly associated with incident hypertension (Table). Mutations in DNMT3A and TET2 but not ASXL1 drove this association. Mediation analysis revealed 17.9% (9.4% - 38.2%, P&lt;0.001) of the effect of CHIP on HF and 5.7% (2.4% - 22.4%, P&lt;0.001) of the effect on HS were mediated through the increased risk of hypertension. Conclusion: CHIP is associated with an increased risk of hypertension. The association of CHIP with HF and HS is partially mediated by hypertension. These findings suggest a new mechanistic pathway for the association of CHIP with cardiovascular diseases.

Abstract 16989: Clonal Hematopoiesis of Indeterminate Potential Status is Associated With Left Main Artery Stenosis

Introduction: Clonal hematopoiesis of indeterminate potential (CHIP) occurs secondary to acquired mutations in bone marrow progenitor cells. CHIP confers a twofold risk of atherosclerotic cardiovascular disease (ASCVD). The two most common CHIP mutations are ten eleven translocase 2 (TET2) and DNA methyltransferase 3A (DNMT3A). However, there is limited data on specific cardiovascular phenotypes in this population. Methods: We recruited patients from the Vanderbilt University Medical Center cardiac catheterization laboratory and performed next generation sequencing to assign CHIP status. Multivariable logistic regression models and proportional odds models were used to assess the association between CHIP status and coronary angiography. Results: We sequenced 1,469 patients, and 1,149 had complete angiographic data. Of these, 214 (18.6%) had CHIP mutations with a variant allele frequency of &gt;2%. CHIP patients were significantly older (68 vs. 59 years, p = 7.7 x 10-16). CHIP carrier status was significantly correlated with any stenosis and degree of stenosis in the left main (LM) coronary artery (OR 1.87 [1.28-2.74]; P = 0.0013 and OR 2.12 [1.42-3.15]; P = 2.2 x 10-4). This association was stronger among patients with TET2 CHIP, both for any LM stenosis (OR 2.98 [1.48 - 5.96]; P = 0.0021) and the degree of LM stenosis (OR 3.52 [1.78 - 6.95]; P = 2.9 x 10-4) (Fig. 1). TET2 CHIP was also correlated with obstructive (&gt;70%) stenosis in any vessel (OR 2.28 [1.15 - 4.52]; P = 0.019), and the number of obstructive stenoses across coronary vessels (OR 1.83 [1.04 - 3.23]; P = 0.037). Conclusions: This is the first description of a specific atherosclerotic phenotype in CHIP and serves as a basis for understanding enhanced morbidity and mortality in CHIP. Our findings reveal a population enriched for CHIP carriers in the catheterization laboratory, an important observation for future studies focused on secondary prevention in CHIP-related ASCVD.