Chromosomal Alterations Research Articles

The Contribution of Mosaic Chromosomal Alterations to Schizophrenia

BackgroundMosaic chromosomal alterations are implicated in neuropsychiatric disorders, but the contribution to schizophrenia (SCZ) risk for somatic copy number variations (sCNVs) emerging in early developmental stages has not been fully established. MethodsWe analyzed blood-derived genotype arrays from 9715 patients with SCZ and 28,822 control participants of Chinese descent using a computational tool (MoChA) based on long-range chromosomal information to detect mosaic chromosomal alterations. We focused on probable early developmental sCNVs through stringent filtering. We assessed the burden of sCNVs across varying cell fraction cutoffs, as well as the frequency with which genes were involved in sCNVs. We integrated this data with the PGC (Psychiatric Genomics Consortium) dataset, which comprises 12,834 SCZ cases and 11,648 controls of European descent, and complemented it with genotyping data from postmortem brain tissue of 936 participants (449 cases and 487 controls). ResultsPatients with SCZ had a significantly higher somatic losses detection rate than control participants (1.00% vs. 0.52%; odds ratio = 1.91; 95% CI, 1.47–2.49; two-sided Fisher’s exact test, p = 1.49 × 10−6). Further analysis indicated that the odds ratios escalated proportionately (from 1.91 to 2.78) with the increment in cell fraction cutoffs. Recurrent sCNVs associated with SCZ (odds ratio > 8; Fisher’s exact test, p < .05) were identified, including notable regions at 10q21.1 (ZWINT), 3q26.1 (SLITRK3), 1q31.1 (BRINP3) and 12q21.31-21.32 (MGAT4C and NTS) in the Chinese cohort, and some regions were validated with PGC data. Cross-tissue validation pinpointed somatic losses at loci like 1p35.3-35.2 and 19p13.3-13.2. ConclusionsThe study highlights the significant impact of mosaic chromosomal alterations on SCZ, suggesting their pivotal role in the disorder’s genetic etiology.

Host Nuclear Genome Copy Number Variations Identify High-Risk Anal Precancers in People Living With HIV.

People living with HIV (PLWH) have substantially increased incidence of anal precancer and cancer. There are very little data regarding genomic disturbances in anal precancers among PLWH. In this study, specific chromosomal variants were identified in anal squamous intraepithelial lesions. Overall, 63 anal biopsy specimens (27 low-grade intraepithelial lesions [LSIL] and 36 high-grade intraepithelial lesions [HSIL]) were collected from PLWH obtained as part of anal cancer screening in our NYC-based health system. Data on patient demographics, anal cytological, and high-risk human papillomavirus (HR-HPV) diagnoses were collected. Specimens were tested for a panel of chromosomal alterations associated with HPV-induced oncogenesis using fluorescence in situ hybridization, and analyses compared the associations of these alterations with clinical characteristics. Gains of 3q26, 5p15, 20q13, and cen7 were detected in 42%, 31%, 31%, and 19% of HSIL compared with 7%, 0%, 4%, and 0% of LSIL, respectively. If at least 1 abnormality was observed, 89% had a 3q26 gain. In lesions with 5p15 gains, 20q13 gains co-occurred in 91% of cases, while cen7 gain only co-occurred with the other 3 alterations. The sensitivity and specificity of any alteration to predict HSIL were 47% (95% CI: 30%-65%) and 93% (95% CI: 76%-99%), respectively. Genomic alterations seen in HPV-associated cancers may help distinguish anal LSIL from HSIL. 3q26 amplification may be an early component of anal carcinogenesis, preceding 5p16, 20q13, and/or chr7. Insights into potential genomic biomarkers for discriminating high-risk anal precancers are shared.

Associations between mosaic loss of sex chromosomes and incident hospitalization for atrial fibrillation in the United Kingdom.

Mosaic loss of chromosome Y (mLOY) in leukocytes of men reflects genomic instability from aging, smoking, and environmental exposures. A similar mosaic loss of chromosome X (mLOX) occurs among women. However, the associations between mLOY, mLOX, and risk of incident heart diseases are unclear. We estimated associations between mLOY, mLOX, and risk of incident heart diseases requiring hospitalization, including atrial fibrillation, myocardial infarction, ischemic heart disease, cardiomyopathy, and heart failure. We analyzed 190,613 men and 224,853 women with genotyping data from the UK Biobank. Among these participants, we analyzed 37,037 men with mLOY and 13,978 women with mLOX detected using Mosaic Chromosomal Alterations caller. Multivariable Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of each incident heart disease in relation to mLOY in men and mLOX in women. Additionally, Mendelian randomization (MR) was conducted to estimate causal associations. Among men, detectable mLOY was associated with elevated risk of atrial fibrillation (HR=1.06, 95%CI:1.03-1.11). The associations were apparent in both never-smokers (HR=1.07, 95%:1.01-1.14) and ever-smokers (HR=1.05, 95%CI:1.01-1.11) as well as men > and ≤60 years of age. MR analyses supported causal associations between mLOY and atrial fibrillation (HRMR-PRESSO=1.15, 95%CI:1.13-1.18). Among post-menopausal women, we found a suggestive inverse association between detectable mLOX and atrial fibrillation risk (HR=0.90, 95%CI:0.83-0.98). However, associations with mLOY and mLOX were not found for other heart diseases. Our findings suggest that mLOY and mLOX reflect sex-specific biological processes or exposure profiles related to incident atrial fibrillation requiring hospitalization.

Association of Mosaic Chromosomal Alterations and Genetic Factors with the Risk of Cirrhosis.

Age-related mosaic chromosomal alterations (mCAs) detected from genotyping of blood-derived DNA are structural somatic variants that indicate clonal hematopoiesis. This study aimed to investigate whether mCAs contribute to the risk of cirrhosis and modify the effect of a polygenic risk score (PRS) on cirrhosis risk prediction. mCA call sets of individuals with European ancestry were obtained from the UK Biobank. The PRS was constructed based on 12 susceptible single-nucleotide polymorphisms for cirrhosis. Cox proportional hazard models were applied to evaluate the associations between mCAs and cirrhosis risk. Among 448,645 individuals with a median follow-up of 12.5 years, we identified 2,681 cases of cirrhosis, 1,775 cases of compensated cirrhosis, and 1,706 cases of decompensated cirrhosis. Compared to non-carriers, individuals with copy-neutral loss of heterozygosity mCAs had a significantly increased risk of cirrhosis (hazard ratio (HR) 1.42, 95% confidence interval (CI) 1.12-1.81). This risk was higher in patients with expanded cell fractions of mCAs (cell fractions ≥10% vs. cell fractions <10%), especially for the risk of decompensated cirrhosis (HR 2.03 [95% CI 1.09-3.78] vs. 1.14 [0.80-1.64]). In comparison to non-carriers of mCAs with low genetic risk, individuals with expanded copy-neutral loss of heterozygosity and high genetic risk showed the highest cirrhosis risk (HR 5.39 [95% CI 2.41-12.07]). The presence of mCAs is associated with increased susceptibility to cirrhosis risk and could be combined with PRS for personalized cirrhosis risk stratification.

Proteogenomic characterization of difficult-to-treat breast cancer with tumor cells enriched through laser microdissection

BackgroundBreast cancer (BC) is the most commonly diagnosed cancer and the leading cause of cancer death among women globally. Despite advances, there is considerable variation in clinical outcomes for patients with non-luminal A tumors, classified as difficult-to-treat breast cancers (DTBC). This study aims to delineate the proteogenomic landscape of DTBC tumors compared to luminal A (LumA) tumors.MethodsWe retrospectively collected a total of 117 untreated primary breast tumor specimens, focusing on DTBC subtypes. Breast tumors were processed by laser microdissection (LMD) to enrich tumor cells. DNA, RNA, and protein were simultaneously extracted from each tumor preparation, followed by whole genome sequencing, paired-end RNA sequencing, global proteomics and phosphoproteomics. Differential feature analysis, pathway analysis and survival analysis were performed to better understand DTBC and investigate biomarkers.ResultsWe observed distinct variations in gene mutations, structural variations, and chromosomal alterations between DTBC and LumA breast tumors. DTBC tumors predominantly had more mutations in TP53, PLXNB3, Zinc finger genes, and fewer mutations in SDC2, CDH1, PIK3CA, SVIL, and PTEN. Notably, Cytoband 1q21, which contains numerous cell proliferation-related genes, was significantly amplified in the DTBC tumors. LMD successfully minimized stromal components and increased RNA–protein concordance, as evidenced by stromal score comparisons and proteomic analysis. Distinct DTBC and LumA-enriched clusters were observed by proteomic and phosphoproteomic clustering analysis, some with survival differences. Phosphoproteomics identified two distinct phosphoproteomic profiles for high relapse-risk and low relapse-risk basal-like tumors, involving several genes known to be associated with breast cancer oncogenesis and progression, including KIAA1522, DCK, FOXO3, MYO9B, ARID1A, EPRS, ZC3HAV1, and RBM14. Lastly, an integrated pathway analysis of multi-omics data highlighted a robust enrichment of proliferation pathways in DTBC tumors.ConclusionsThis study provides an integrated proteogenomic characterization of DTBC vs LumA with tumor cells enriched through laser microdissection. We identified many common features of DTBC tumors and the phosphopeptides that could serve as potential biomarkers for high/low relapse-risk basal-like BC and possibly guide treatment selections.

Genetic variability profiling of the p53 signaling pathway in chronic lymphocytic leukemia. Individual and combined analysis of TP53, MDM2 and NQO1 gene variants.

TP53 gene disruption, including 17p13 deletion [del(17p)] and/or TP53 mutations, is a negative prognostic biomarker in chronic lymphocytic leukemia (CLL) associated with disease progression, treatment failure and shorter survival. Germline variants in p53 signaling pathway genes could also lead to p53 dysfunction, but their involvement in CLL has not been thoroughly evaluated. The aim of this study was to determine the association of TP53, MDM2 and NQO1 gene variability with clinical and genetic data of CLL patients. Individual genotype and haplotype data of CLL patients were compared with clinical prognostic factors, cytogenetic and molecular cytogenetic findings as well as IGHV and TP53 mutational status. The study included 116 CLL patients and 161 healthy blood donors. TP53 (rs1042522, rs59758982, rs1625895), NQO1 (rs1800566) and MDM2 (rs2279744, rs150550023) variants were genotyped using different PCR approaches. Analysis of genotype frequencies revealed no association with the risk of CLL. TP53 rs1042522, rs1625895 and MDM2 rs2279744 variants were significantly associated with abnormal karyotype and the presence of del(17p). Similarly, these two TP53 variants were associated with TP53 disruption. Moreover, TP53 C-A-nondel and G-A-del haplotypes (rs1042522-rs1625895-rs59758982) were associated with an increased likelihood of carrying del(17p) and TP53 disruptions. MDM2 T-nondel haplotype (rs2279744-rs150550023) was found to be a low risk factor for del(17p) (OR = 0.32; CI: 0.12-0.82; p = 0.02) and TP53 disruptions (OR = 0.41; CI: 0.18-0.95; p = 0.04). Our findings suggest that TP53 and MDM2 variants may modulate the risk to have chromosome alterations and TP53 disruptions, particularly del(17p). To our knowledge this is the first study of several germline variants in p53 pathway genes in Argentine patients with CLL.

Determinants of mosaic chromosomal alteration fitness

Clonal hematopoiesis (CH) is characterized by the acquisition of a somatic mutation in a hematopoietic stem cell that results in a clonal expansion. These driver mutations can be single nucleotide variants in cancer driver genes or larger structural rearrangements called mosaic chromosomal alterations (mCAs). The factors that influence the variations in mCA fitness and ultimately result in different clonal expansion rates are not well understood. We used the Passenger-Approximated Clonal Expansion Rate (PACER) method to estimate clonal expansion rate as PACER scores for 6,381 individuals in the NHLBI TOPMed cohort with gain, loss, and copy-neutral loss of heterozygosity mCAs. Our mCA fitness estimates, derived by aggregating per-individual PACER scores, were correlated (R2 = 0.49) with an alternative approach that estimated fitness of mCAs in the UK Biobank using population-level distributions of clonal fraction. Among individuals with JAK2 V617F clonal hematopoiesis of indeterminate potential or mCAs affecting the JAK2 gene on chromosome 9, PACER score was strongly correlated with erythrocyte count. In a cross-sectional analysis, genome-wide association study of estimates of mCA expansion rate identified a TCL1A locus variant associated with mCA clonal expansion rate, with suggestive variants in NRIP1 and TERT.

Abstract Wrk2-01: Organoid Models of Cancer and the Tumor Microenvironment

Abstract Both cell-intrinsic and microenvironmental influences vitally govern tumor progression. Mutational, chromosomal and epigenetic alterations represent the former, while the latter is influenced by diverse stromal populations including fibroblasts, vasculature and immune cells. In vitro organoid culture provides an experimentally tractable platform for cancer research that is applicable to cell-autonomous and tumor microenvironmental studies. The first part of this lecture will describe our work using organoid culture to functionally validate tumor cell-intrinsic genomic alterations. Notably, cancer research has traditionally lacked in vitro methods where tumors can be holistically cultured in a non-reconstitutive manner that co-preserves neoplastic cells together with endogenous stromal components. Thus, the second part of this lecture will describe advances in 3D tumor organoid culture that allow growth of cancer cells in a manner that preserves their native interaction with diverse tumor-infiltrating immune cells and allows analysis of immune checkpoint inhibition. Citation Format: C. Kuo. Organoid Models of Cancer and the Tumor Microenvironment [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr Wrk2-01.

CNS Germ Cell Tumors: Molecular Advances, Significance in Risk Stratification and Future Directions.

Central Nervous System Germ Cell Tumors (CNS GCTs) represent a subtype of intracranial malignant tumors characterized by highly heterogeneous histology. Current diagnostic methods in clinical practice have notable limitations, and treatment strategies struggle to achieve personalized therapy based on patient risk stratification. Advances in molecular genetics, biology, epigenetics, and understanding of the tumor microenvironment suggest the diagnostic potential of associated molecular alterations, aiding risk subgroup identification at diagnosis. Furthermore, they suggest the existence of novel therapeutic approaches targeting chromosomal alterations, mutated genes and altered signaling pathways, methylation changes, microRNAs, and immune checkpoints. Moving forward, further research is imperative to explore the pathogenesis of CNS GCTs and unravel the intricate interactions among various molecular alterations. Additionally, these findings require validation in clinical cohorts to assess their role in the diagnosis, risk stratification, and treatment of patients.

First Transcriptome Analysis of Hepatoblastoma in Brazil: Unraveling the Pivotal Role of Noncoding RNAs and Metabolic Pathways.

Hepatoblastoma stands as the most prevalent liver cancer in the pediatric population. Characterized by a low mutational burden, chromosomal and epigenetic alterations are key drivers of its tumorigenesis. Transcriptome analysis is a powerful tool for unraveling the molecular intricacies of hepatoblastoma, shedding light on the effects of genetic and epigenetic changes on gene expression. In this study conducted in Brazilian patients, an in-depth whole transcriptome analysis was performed on 14 primary hepatoblastomas, compared to control liver tissues. The analysis unveiled 1,492 differentially expressed genes (1,031 upregulated and 461 downregulated), including 920 protein-coding genes (62%). Upregulated biological processes were linked to cell differentiation, signaling, morphogenesis, and development, involving known hepatoblastoma-associated genes (DLK1, MEG3, HDAC2, TET1, HMGA2, DKK1, DKK4), alongside with novel findings (GYNG4, CDH3, and TNFRSF19). Downregulated processes predominantly centered around oxidation and metabolism, affecting amines, nicotinamides, and lipids, featuring novel discoveries like the repression of SYT7, TTC36, THRSP, CCND1, GCK and CAMK2B. Two genes, which displayed a concordant pattern of DNA methylation alteration in their promoter regions and dysregulation in the transcriptome, were further validated by RT-qPCR: the upregulated TNFRSF19, a key gene in the embryonic development, and the repressed THRSP, connected to lipid metabolism. Furthermore, based on protein-protein interaction analysis, we identified genes holding central positions in the network, such as HDAC2, CCND1, GCK, and CAMK2B, among others, that emerged as prime candidates warranting functional validation in future studies. Notably, a significant dysregulation of non-coding RNAs (ncRNAs), predominantly upregulated transcripts, was observed, with 42% of the top 50 highly expressed genes being ncRNAs. An integrative miRNA-mRNA analysis revealed crucial biological processes associated with metabolism, oxidation reactions of lipids and carbohydrates, andmethylation-dependent chromatin silencing. In particular, four upregulated miRNAs (miR-186, miR-214, miR-377, and miR-494) played a pivotal role in the network, potentially targeting multiple protein-coding transcripts, including CCND1 and CAMK2B. In summary, our transcriptome analysis highlighted disrupted embryonic development as well as metabolic pathways, particularly those involving lipids, emphasizing the emerging role of ncRNAs as epigenetic regulators in hepatoblastomas. These findings provide insights into the complexity of the hepatoblastoma transcriptome and identify potential targets for future therapeutic interventions.

Chromosomal Damage, Chromosome Instability, and Polymorphisms in GSTP1 and XRCC1 as Biomarkers of Effect and Susceptibility in Farmers Exposed to Pesticides.

In the department of Boyacá, Colombia, agriculture stands as one of the primary economic activities. However, the escalating utilization of pesticides within this sector has sparked concern regarding its potential correlation with elevated risks of genotoxicity, chromosomal alterations, and carcinogenesis. Furthermore, pesticides have been associated with a broad spectrum of genetic polymorphisms that impact pivotal genes involved in pesticide metabolism and DNA repair, among other processes. Nonetheless, our understanding of the genotoxic effects of pesticides on the chromosomes (as biomarkers of effect) in exposed farmers and the impact of genetic polymorphisms (as susceptibility biomarkers) on the increased risk of chromosomal damage is still limited. The aim of our study was to evaluate chromosomal alterations, chromosomal instability, and clonal heterogeneity, as well as the presence of polymorphic variants in the GSTP1 and XRCC1 genes, in peripheral blood samples of farmers occupationally exposed to pesticides in Aquitania, Colombia, and in an unexposed control group. Our results showed statistically significant differences in the frequency of numerical chromosomal alterations, chromosomal instability, and clonal heterogeneity levels between the exposed and unexposed groups. In addition, we also found a higher frequency of chromosomal instability and clonal heterogeneity in exposed individuals carrying the heterozygous GSTP1 AG and XRCC1 (exon 10) GA genotypes. The evaluation of chromosomal alterations and chromosomal instability resulting from pesticide exposure, combined with the identification of polymorphic variants in the GSTP1 and XRCC1 genes, and further research involving a larger group of individuals exposed to pesticides could enable the identification of effect and susceptibility biomarkers. Such markers could prove valuable for monitoring individuals occupationally exposed to pesticides.

Abstract NG03: Functional and computational approaches to uncover selection advantages of cancer aneuploidy

Abstract Aneuploidy, including the gain or loss of whole chromosomes or chromosome arms, is a near-universal feature of cancer. We previously applied methods that define chromosome arm aneuploidy to over 10,000 tumors in the Cancer Genome Atlas (TCGA). Cancer subtypes are often characterized by tumor specific patterns of chromosome arm copy number alterations and breakpoints; for example, squamous cell carcinomas (SCCs) from different tissues of origin are characterized by chromosome 3p (chr3p) loss and chromosome 3q (chr3q) gain. From the TCGA aneuploidy data, we developed an algorithm called BISCUT to distinguish peak regions of aneuploidy breakpoints on each chromosome arm. BISCUT identified loci affected by broad copy number alterations that provide fitness advantages or disadvantages both within individual cancer types and across cancers. Our analyses are consistent with selection being the primary driver of aneuploidy events in cancer. We next wanted to validate some BISCUT peaks without a known driver, to identify potential gene deletions that are beneficial in cancer cells. We focused on chromosome 8p (chr8p), as this arm is frequently deleted across cancer types, but no strong tumor suppressors have been identified. Recent advances in genome engineering allow generation of large chromosomal alterations and validation of findings from patient genomic data. For this study, we used our CRISPR-Cas9 arm-deletion system to delete chr8p in human immortalized epithelial cells. Cells with chr8p deletion showed lower amounts of cell death in culture. Knockdown of WRN, one of the two genes in the smallest chr8p BISCUT peak, was sufficient to reproduce this phenotype, suggesting that WRN haploinsufficiency may be beneficial to tumor development. As aneuploidy occurs in tissue-specific patterns, we also wanted to explore the role of chr3 arm aneuploidies in squamous cancers. We again used the CRISPR-Cas9 system to delete one copy of chr3p in a human immortalized lung epithelial cell line similar to the putative cell-of-origin in lung SCC. Consistent with patient data, expression of chr3p genes was decreased upon deletion, as well as increased expression of interferon response genes. Cells with chr3p deletion initially proliferated more slowly than their siblings. Interestingly, after several passages in culture, this proliferation defect was rescued in chr3p deleted cells. Genome sequencing and karyotype analyses suggested that this was partially the result of chr3 duplication, with cells transitioning to a state of chr3q gain. Culturing these cells as organoids also demonstrated that chr3p deletion and chr3q gain can affect basal cell differentiation, consistent with their high frequency in squamous cancers. Our genome engineering approach to model chromosome arm aneuploidies provides a robust model to validate drivers from aneuploidy events, which will be critical to address the gap in our understanding of aneuploidy in cancer. In addition, our methods have identified consequences of individual aneuploidy events, which will lead to new precision oncology targets for patients. Citation Format: Alison M. Taylor. Functional and computational approaches to uncover selection advantages of cancer aneuploidy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr NG03.

Not Only RET but NF1 and Chromosomal Instability Are Seen in Young Patients with Sporadic Medullary Thyroid Carcinoma.

Genetic analysis of sporadic medullary thyroid carcinoma (MTC) has revealed somatic variants in RET, RAS, and occasionally other genes. However, around 20% of patients with sporadic MTC lack a known genetic driver. To uncover potential new somatic or germline drivers, we analyze a distinct cohort of patients with sporadic, very early-onset, and aggressive MTC. Germline and somatic DNA exome sequencing was performed in 19 patients, previously tested negative for germline RET variants. Exome sequencing of 19 germline samples confirmed the absence of RET and identified an NF1 pathogenic variant in 1 patient. Somatic sequencing was successful in 15 tumors revealing RET variants in 80%, predominantly p.Met918Thr, which was associated with disease aggressiveness. In RET-negative tumors, pathogenic variants were found in HRAS and NF1. The NF1 germline and somatic variants were observed in a patient without a prior clinical diagnosis of neurofibromatosis type 1, demonstrating that the loss of heterozygosity of NF1 functions as a potential MTC driver. Somatic copy number alterations analysis revealed chromosomal alterations in 53.3% of tumors, predominantly in RET-positive cases, with losses in chromosomes 9 and 22 being the most prevalent. This study reveals that within a cohort of early-onset nonhereditary MTC, RET remains the major driver gene. In RET-negative tumors, NF1 and RAS are drivers of sporadic MTC. In addition, in young patients without a RET germline mutation, a careful clinical evaluation with a consideration of germline NF1 gene analysis is ideal to exclude Neurofibromatosis type 1 (NF1).

Abstract 3634: Copy number alterations in chromosome 19 genes associate with reduced immune infiltrate and adverse outcomes in lung cancer

Abstract Deleterious mutations in STK11/LKB1, KEAP1, and SMARCA4 have been shown to be associated with adverse response to immunotherapy in several lung cancer cohorts. However, the biological and clinical implications of deletions of these genes, which all reside on chromosome 19p (chr19p), has not been extensively described. We sought to first characterize the association between immune infiltration and these copy number changes in chr19p. To do this, we analyzed mutation, copy number, and gene expression data from non-small cell lung cancer cohorts in the Cancer Genome Atlas (TCGA). Chr19p is frequently deleted across cancers in the TCGA dataset, with higher rates in lung adenocarcinoma. In both lung adenocarcinoma and squamous cell carcinoma, nearly half of TCGA tumors have deletion of chr19p including STK11, KEAP1, and SMARCA4, and these tumors are enriched for STK11 mutation. Immune infiltrate (estimated by methylation patterns) was not significantly associated with STK11 mutation but was significantly reduced in tumors with chr19 deletion when controlling for tumor type and overall copy number load. In addition, low-level deletion of any of these genes correlated with decreased expression of immune signaling pathways. Based on these findings, we next wanted to characterize the association between chr19p copy number and immunotherapy response. We previously reported that low-level deletion of STK11 correlated with an immunosuppressive, treatment-refractory phenotype in samples collected from non-small cell lung cancer (NSCLC) patients with resectable disease in a phase II study of neoadjuvant atezolizumab + chemotherapy. To confirm these findings in a larger cohort, we examined the AACR GENIE NSCLC biopharma collective (BPC) dataset. A subset of this cohort included patients treated with immunotherapy (atezolizumab, nivolumab, and/or pembrolizumab) and with copy number data available or GISTIC analysis of individual genes (n = 204). Here, deletion of any of these three genes correlated with worse overall survival, and this was statistically significant for STK11 deletion. Overall, our data suggests that a broader set of patients, defined by copy number changes in these genes, may experience this adverse immunobiology. Further study to elucidate the mechanistic implications of this association is warranted. Citation Format: Brian S. Henick, Yohanna Georgis, Benjamin O. Herzberg, Carla P. Concepcion-Crisol, Alison M. Taylor. Copy number alterations in chromosome 19 genes associate with reduced immune infiltrate and adverse outcomes in lung 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 3634.

Abstract 4334: Insight into the structure of breakage fusion bridge events and chromothripsis in cancer cell lines using long-read sequencing

Abstract Cervical cancer is caused by human papillomavirus (HPV) infection and is the most common cause of cancer death in low-resource countries. We characterized 18 cervical and 4 head and neck cancer cell lines using long-read DNA and RNA sequencing and identified the HPV types, HPV integration sites, and cancer driver mutations. This cell line panel represents the major molecular subtypes of cervical cancer. Structural variation analysis revealed recurrent chromosomal alteration and telomeric deletions associated with DNA inversions resulting from breakage-fusion-bridge (BFB) cycles. BFB is a common mechanism of chromosomal alteration in cancer that has not been studied using long-read sequencing. Analysis of the inversion sites revealed staggered ends consistent with exonuclease deletion of the DNA after breakage. Some BFB events are complex, involving interchromosomal or intrachromosomal insertions or rearrangements. In total, there were three different types of BFB events: Type I, II, and III. Type I BFB events have staggered ends but no additional insertion at the fusion site. Type II BFB events have an insertion of DNA from another chromosome at the junction, and Type III has an insertion of sequences from the same chromosome as the BFB. BFB cycles are thought to resolve with the addition of a telomere. However, a search for telomeric sequences did not identify any on chromosomes impacted by BFB. In many cancers, BFB events co-occur with chromothripsis; however, in our cervical cancers, only 1 out of 13 had chromosomal shattering near the BFB event, indicating that the mechanism of chromosome rearrangement may be different in cervical cancers. Five cell lines have a Chr11q BFB event, with YAP1/BIRC2/BIRC3 gene amplification. Analysis of 911 publicly available cervical cancer exomes showed that YAP1 amplification is associated with a 10-year earlier age of diagnosis of cervical cancer (x2, p&amp;lt;0.0001) and is three times more common in African Americans (x2=12, p=0.003). Therefore, cervical cancer patients with YAP1/BIRC2/BIRC3 amplification, especially those of African American ancestry, might benefit from anti-YAP1/BIRC2/BIRC3 therapies. Our panel provides models for all the major HPV types and subtypes of cervical cancer that will aid in developing new therapeutic approaches. In summary, we uncovered novel insights into the mechanisms and consequences of BFB cycles in cervical cancer using long-read sequencing. We are expanding long-read sequencing to other cancer cell lines to gain knowledge of events associated with BFB. Citation Format: Isabel Rodriguez, Nicole Rossi, Ayse Gokce Kesus, Yi Xie, Tanveer Ahmad, Asher Bryant, Hong Lou, Jesica Godinez Paredes, Rose Milano, Mikhail Kolmogorov, Sonam Tulsyan, Jazmyn Bess, Vera Mukhina, Daria Gaykalova, Laksh Malik, Kimberley J. Billingsley, Cornelis Blauwendraat, Lisa Mirabello, Michael Dean. Insight into the structure of breakage fusion bridge events and chromothripsis in cancer cell lines using long-read sequencing [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 4334.

Abstract 4907: RanBALL: Identifying B-cell acute lymphoblastic leukemia subtypes based on an ensemble random projection model

Abstract As the most common pediatric malignancy, B-cell acute lymphoblastic leukemia (B-ALL) has multiple distinct subtypes characterized by recurrent and sporadic somatic and germline genetic alterations like chromosomal alteration, transcription factor rearrangement or kinase inhibition. The treatment of B-ALL patients is personalized based on specific subtypes, as the treatment responses for different B-ALL subtypes may vary considerably. Identification of B-ALL subtypes can facilitate risk stratification and enable tailored therapeutic approaches. Existing methods for B-ALL subtyping primarily depend on immunophenotypic, cytogenetic and genomic analyses, which would be costly, complicated, and laborious in clinical practice applications. To overcome these challenges, we present RanBALL (an Ensemble Random Projection-Based Model for Identifying B-Cell Acute Lymphoblastic Leukemia Subtypes), an accurate and cost-effective model for B-ALL subtype identification based on transcriptomic profiling only. RanBALL leverages random projection (RP) to construct an ensemble of dimension-reduced multi-class classifiers for B-ALL subtyping. Specifically, the transcriptomic profiling features were projected onto low-dimensional spaces by random projection matrices whose elements conform to a distribution characterized by zero mean and unit variance. To ensure reliable and robust performance, we selected 20 subspace dimensions ranging from 600 to 2500, with intervals of 100. The transformed low dimensional data matrix was used for training an ensemble of multi-class support vector machine (SVM) classifiers, each corresponding to one of the RP matrices of various dimensions. The predicted probabilistic scores of each B-ALL subtype were integrated for determining the final decision. Results based on 10 times 10-fold cross validation tests for &amp;gt;1700 B-ALL patients demonstrated that the proposed model achieved an accuracy of 93.7%, indicating promising prediction capabilities of RanBALL for B-ALL subtyping. Furthermore, the 30% held-out tests suggested that the model was robust and consistent to maintain high confidence levels for accurate predictions. The high accuracies of RanBALL suggested that our model could effectively capture underlying patterns of transcriptomic profiling for accurate B-ALL subtype identification. To extend the impact of RanBALL, we have established a free and publicly available python package for RanBALL available at https://github.com/wan-mlab/RanBALL. We believe RanBALL will facilitate the discovery of B-ALL subtype-specific marker genes and therapeutic targets, and eventually have consequential positive impacts on downstream risk stratification and tailored treatment design. Citation Format: Lusheng Li, Hanyu Xiao, Joseph D. Khoury, Jieqiong Wang, Shibiao Wan. RanBALL: Identifying B-cell acute lymphoblastic leukemia subtypes based on an ensemble random projection model [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 4907.

Abstract 6599: 3D genomic analysis reveals novel enhancer hijacking mechanisms caused by complex structural alterations that drive oncogene overexpression

Abstract Enhancer hijacking, caused by structural alterations on chromosomes as well as extrachromosomal DNA (ecDNA), is a common cancer driver event. The complexity and ubiquity of structural alterations in cancer genomes make it difficult to identify enhancer hijacking with genome sequencing alone. Here we describe a 3D genomics-based analysis called HAPI (Highly Active Promoter Interactions) to characterize enhancer hijacking caused by various types of structural alterations. Applying HAPI analysis to HiChIP data from 34 cancer cell lines, we identified novel enhancers hijacked through chromosomal rearrangements to activate both known and potentially novel oncogenes such as MYC, CCND1, ETV1, CRKL, and ID4, which we validated using CRISPRi assays and RNA-seq analysis. Furthermore, we found that ecDNAs often contain multiple oncogenes from different chromosomes, which cause nested enhancer hijacking among them. For instance, we found that MYC ecDNAs relocate additional oncogenes from other chromosomes such as CDX2, ERBB2, or CD44 near the MYC locus, co-opting MYC’s enhancers for their overexpression, which we validated using dual-color DNA FISH and CRISPRi assays. This multiple oncogenes-involved enhancer hijacking mechanism may suggest novel therapeutic strategies such as targeting either the co-opting oncogenes or the hijacked enhancers for ecDNAs. Our study provides a robust strategy to detect enhancer hijacking events using our publicly available HAPI analysis tool and reveals novel mechanisms underlying oncogene activation caused by chromosomal and extrachromosomal structural alterations. Citation Format: Katelyn L. Mortenson, Courtney Dawes, Emily R. Wilson, Nathan E. Patchen, Hailey Johnson, Jason Gertz, Swneke D. Bailey, Yan Liu, Katherine E. Varley, Xiaoyang Zhang. 3D genomic analysis reveals novel enhancer hijacking mechanisms caused by complex structural alterations that drive oncogene overexpression [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 6599.

Abstract 1467: Contribution of estrogen metabolites to never-smoking lung cancer

Abstract There has been a consistent rise in the incidence of non-small cell lung cancer (NSCLC) among individuals who have never smoked. Remarkably, over 50% of diagnosed female cases and 15-20% of male cases are never-smokers. Notably, NSCLC in never-smokers exhibits distinctive clinical and pathological features, notably a higher incidence of tumors with EGFR mutations, setting it apart from its counterpart in smokers. Despite the improved disease-free survival observed with EGFR-tyrosine kinase inhibitors, eventual relapse and limited responsiveness to immunotherapy are common, underscoring the urgency to comprehend the molecular mechanisms driving the escalating prevalence of NSCLC in never-smokers and develop targeted preventive and interceptive therapeutic strategies. The preponderance of females among NSCLC patients who never smoked has prompted an exploration into the potential contribution of estrogen to lung tumorigenesis. In contrast to prevailing research focused on estrogen receptor-mediated signaling, our investigations have yielded compelling evidence supporting the involvement of estrogen metabolism in lung carcinogenesis among never-smokers. This group is the first to report that estrogen is metabolized extensively in both mouse and human lungs, resulting in the generation of various derivatives, including the potential carcinogen 4-hydroxyestrogen (4-OHE). Notably, recent findings from our laboratory indicate that prolonged exposure of nonneoplastic human bronchial epithelial cells to 17β estradiol or 4-OHE, at concentrations approximating physiological levels, induces the accumulation of double-strand DNA breaks and cellular transformation. A comprehensive analysis was performed to further elucidate the mechanisms underlying the transformation process. Isolated transformed clones obtained after 9, 18, and 22 wks of exposure to 4-OHE were subjected to karyotyping, F.I.S.H., and RNA and exome sequencing. A longitudinal progression of aberrant chromosomal rearrangements and copy number alterations was observed, that increased with time of 4-OHE exposure. In addition, RNA-Seq analyses revealed the epithelial-mesenchymal transition pathway was highly enriched at the early timepoint (9 wks), while replicative stress-related signaling pathways were induced at all timepoints. To determine if the differentially expressed genes were also dysregulated in clinical lung cancer cases, TCGA lung adenocarcinoma (LUAD) data were examined. Interestingly, many of the genes upregulated after estrogen exposure were similarly overexpressed in the LUAD samples and often associated with a worse prognosis. In conclusion, our data support the role of estrogen metabolites in promoting lung cancer among never-smokers. (Supported by CA217161 and generous contributions from the Hellendall Family Foundation, Gregory G. Lawton and the Timothy and Aurora Hughes Cancer Research Fund.) Citation Format: Mitchell Cheung, Lisa A. Vanderveer, Daniel Krzizike, J. Nicholas Bodor, Joseph Treat, Joseph R. Testa, Margie L. Clapper. Contribution of estrogen metabolites to never-smoking lung 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 1467.

Abstract 4849: Mosaic chromosomal alterations in a prospective cohort of Mexican Americans for cancer risk and genetic insights

Abstract Introduction: In this study, we aim to explore mosaic chromosomal alterations (mCA) and their implications in cancer risk among Mexican Americans (MA) - an expanding yet historically underrepresented ethnic minority in the U.S. In addition, we propose to develop a novel method that identifies high mutant cell fraction (MCF) copy-neutral Loss of heterozygosity (cn-LOH). At sufficiently high MCF, these will look like runs of homozygosity (ROH) and may be missed by current mCA detection techniques that rely on identified germline heterozygote genotypes. Our preliminary findings revealed frequent and widespread homozygosity across the genome, predominantly in short regions (&amp;lt;10 Mb), although some exceeded 100 Mb. Our objective is to advance mCA detection techniques, differentiating cn-LOH from ROH, to deepen our understanding of mCA. Methods: We analyzed SNP array data from blood and saliva samples of 1657 individuals, focusing on cancer and chronic disease risk ages, from the Mano a Mano Mexican American Cohort Study. We applied hapLOH and MoChA, both haplotype-based methods, to detect mCA. To identify high-MCF cn-LOH, we first scanned for observed ROH using PLINK. Separately, we develop a statistical framework through simulations to differentiate high-MCF cn-LOH from ROH. We considered multiple methods; initially, we built a statistical framework using a hypothesis-testing approach (H0: ROH; H1: cn-LOH), where we compared the “B allele” frequency information within observed ROH. To split this information and obtain our groups, we used population genetic principles. Secondly, we classified our events, calculating the likelihood ratio of our statistical hypotheses. Finally, we explored a haplotype-based imputation approach that leverages flanking diploid region information. Results: We identified numerous mCA, predominantly in individuals without cancer. Simulations showed effective classification in larger homozygosity regions (&amp;gt;10 Mb), guiding our methodological focus on detecting shorter high-MCF regions. Not surprisingly, extremely high MCFs (0.99-1) presented challenges in accurate identification. Conclusion and Future Directions: To improve our mCA results description, we will thoroughly characterize and study their association with cancer phenotypes and environmental exposures. We are in the process of genotyping the entire cohort, which consists of over 25,000 participants. To date, our cohort includes 909 cancer cases, of which 262 are hematological malignancies. We sought to design a unique method that differentiates high-MCF cn-LOH from observed ROH, improving current mCA discovery. Our focus is on small regions as they provide limited information to infer event types. Our next step is to characterize and validate our results, especially in pathologically normal samples, as a way of identifying potential biomarkers of interest. Citation Format: Jessica Valdebenito, Justin Wong, Dahwei Chang, Henry Gomez, Kevin T Nead, Yasminka Jakubek, Paul Scheet. Mosaic chromosomal alterations in a prospective cohort of Mexican Americans for cancer risk and genetic insights [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 4849.

Abstract 2205: Modifiable risk factors are associated with clonal hematopoiesis

Abstract Observational studies have implicated modifiable factors like smoking, alcohol intake, physical activity (PA), and sleep to cancer risk. Clonal hematopoiesis (CH), marked by clonal expansions of mutated hematopoietic progenitors with mosaic chromosomal alterations (mCAs) or clonal hematopoiesis of indeterminate potential (CHIP), has been associated with the risk of serval cancers and may shed light the interplay between these factors and early preneoplastic hematopoietic expansion.Leveraging genotyping array and whole-exome sequencing data of leukocyte-derived DNA from 485,028 participants without hematologic malignancies in the UK Biobank (UKBB), we performed genome-wide characterization of two common forms of CH—mCAs and CHIP. To assess associations between social deprivation, self-reported modifiable risk factors, and CH risk, we employed multivariable logistic regression models adjusted for potential confounders including age, sex, smoking history, and genetic ancestry.We identified 11,826 (2.4%) individuals with autosomal mosaic chromosomal alterations (auto mCAs), 15,499 (3.2%) with loss of the X chromosome (mLOX), 43,044 (8.8%) with loss of the Y chromosome (mLOY) and 22,508 (4.6%) with CHIP. Individuals with any CH subtype were on average older than CH-free individuals (p &amp;lt; 9.11 × 10−52). Multivariable models identified a significant negative association between mLOY and social deprivation in England (1 SD change in score: OR = 0.968 [0.956-0.980], p = 4.88 × 10−7), suggesting modifiable risk factors could influence risk of mLOY. We observed a positive association with ever smoking and CH, which decreased with increased years since smoking cessation. Current smokers were at higher risk for auto mCAs (Odds ratio (OR) = 1.23, 95% Confidence Interval (CI):[1.16-1.31], P-value (p) = 2.63 × 10−11), mLOY (OR = 2.25, 95%CI: [2.17-2.33], p &amp;lt; 9.11 × 10−52), and CHIP (OR = 1.40,, 95%CI: [1.34-1.47] p &amp;lt; 9.11 × 10−52); and former smokers also exhibited significant associations for mLOY (OR = 1.16, 95%CI: [1.13-1.19], p = 2.97 × 10−32) and CHIP (OR = 1.11, 95%CI: [1.08-1.15], p = 2.75 × 10−13). Alcohol consumption was associated with a significant increase in the risk of mLOX in heavy drinkers (&amp;gt;2-3 drinks/day) compared to non-drinkers (OR = 1.16, 95%CI: [1.09-1.24], p = 1.21 × 10−5). Moderate and high PA levels (categorized as level 2 and 3 based on total activity), were positively associated with increased mLOY frequency (moderate: OR = 1.05, 95%CI: [1.02-1.08], p = 8.6 × 10−2, high: OR = 1.06, 95%CI: [1.03-1.08], p = 1.6 × 10−3). We observed no evidence for an association between sleep patterns and CH.Our investigation in a large cohort identified associations between CH and social deprivation, smoking, alcohol consumption and PA. As CH is an intermediate marker for hematologic cancer risk, our findings imply that modifiable exposures may contribute to hematologic cancer risk through clonal mechanisms. Citation Format: Corey D. Young, Aubrey K. Hubbard, Pedro Saint-Maurice, Irenaeus Chan, Kelly L. Bolton, Stephen J. Chanock, Charles Matthews, Steven C. Moore, Erikka Loftfield, Yin Cao, Mitchell J. Machiela, Duc Tran. Modifiable risk factors are associated with 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 2205.