Repair Deficiency Research Articles

A quality initiative focused on BRCA and HRD testing and use of first line maintenance in advanced ovarian cancer.

286 Background: In May of 2020, the approval of two Poly (ADP-ribose) polymerase inhibitors (PARPi) changed the landscape for treatment among patients (pts) with advanced ovarian cancer (aOC). As such, National Comprehensive Cancer Network guidelines recommend BRCA testing for individuals with epithelial ovarian cancer and Homologous Recombination Repair Deficiency (HRD) testing for pts who are BRCA germline negative to guide the decision of maintenance therapy. Regional Cancer Care Associates (RCCA) conducted a quality initiative (QI) with Integra Connect PrecisionQ to assess the rates of BRCA testing, HRD testing, and use of first line maintenance (LOT 1M) therapy based on biomarker status. This QI focused on interventions to optimize testing and LOT 1M treatment in these pts. We aim to show the improvement in BRCA testing, HRD testing, and rates of LOT 1M therapy use after implementation of the QI, in pts with aOC at RCCA. Methods: Using the de-identified IC PrecisionQ database, 90 RCCA pts with aOC as defined by stage III and IV were selected for medical chart curation at baseline. Pts in the baseline group received first-line treatment between 1/1/2020 to 5/31/2022. The baseline data was reviewed with RCCA clinical leadership and findings were presented at a standing practice clinical meeting on 6/20/2024. Post-baseline, we evaluated 28 aOC pts who started a new first-line of therapy between 7/1/2023 to 4/30/2024 to assess BRCA and HRD testing rates and use of LOT 1M among maintenance eligible (ME) pts. ME was defined by a complete response, partial response, or for those where no response was known and had either received maintenance or had no subsequent treatment after 180 days of completing first line therapy. Maintenance therapies included PARPi(s) and bevacizumab. Descriptive analyses were performed and proportions were compared using a chi-squared test. Results: The baseline cohort had 90 pts of which 66% were stage III and 34% were stage IV. The post-baseline cohort had 28 pts of which 54% were stage III and 46% were stage IV. The rate of BRCA testing at baseline was 86% compared to 93% post-baseline. The rate of HRD testing at baseline was 41% compared to 71% post-baseline (p <0.01). The rate of LOT 1M use among maintenance eligible pts at baseline was 57% (N=76) compared to 78% (N=23) post-baseline. PARPi maintenance at baseline was 67% (N=43) compared to 67% (N=14) post-baseline. While rates of maintenance therapy use remained the same from baseline to post-baseline for BRCA mutated pts at 80%, the use of maintenance increased in HRD positive pts from 71% (N = 7) to 77% (N=13). Conclusions: The QI at RCCA that focused on BRCA and HRD testing and treatment with LOT 1M among aOC pts led to improvements against clinical guidelines. QI programs are critical to transforming cancer care and can be useful tools to drive improvement in testing and treatment.

Poor compliance with germline testing recommendations in colorectal cancer patients undergoing molecular residual disease testing.

Approximately 15% of colorectal cancers (CRCs) are associated with germline mutations. There is increasing adoption of DNA-based assays for molecular residual disease (MRD) and growing evidence supporting its clinical utility, particularly for CRC by oncologists in the U.S. We assessed the uptake of germline multi-gene panel testing (MGPT) for hereditary cancer in CRC patients receiving MRD analyses in community oncology settings. This retrospective study included 80 patients receiving care for CRC through community oncology practices who were referred for MRD testing at a commercial laboratory (January-March 2022). Clinical data, including test requisition forms, pathology reports, and clinical notes were reviewed. Documentation of tumor microsatellite instability and/or immunohistochemical (IHC) testing for mismatch repair (MMR) deficiency, age of CRC diagnosis, family history of cancer, and any order or recommendation for MGPT were assessed. Overall, 5/80 (6.3%) patients in the study have documented germline MGPT; 65/80 (81.3%) patients have documented MMR testing of their colorectal tumor. Among the 5 cases with abnormal MMR IHC, 2 have MGPT. Of the 33 patients meeting the 2021 National Comprehensive Cancer Network (NCCN) criteria for genetic/familial high-risk assessment, only 2 have MGPT. Our real-world data suggest that many CRC patients receiving MRD testing and meeting NCCN (v. 2021) criteria for germline MGPT may not be receiving evaluation beyond routine MMR status. Process and educational improvements are needed in community health settings to increase access and uptake of germline testing among CRC patients regardless of age at diagnosis or MMR status.

Biallelic Mismatch Repair Deficiency in Children and Adolescents: A Review of Published and Unpublished Data from India—Need for an Indian Consortium

Abstract Introduction Biallelic mismatch repair deficiency or constitutional mismatch repair deficiency (CMMRD) is a rare and aggressive pediatric cancer predisposition syndrome that occurs as a result of homozygous (biallelic) pathogenic variants in mismatch repair genes. The primary malignancies that occur in CMMRD are mainly hematological and brain malignancies. Most published data are from the western populations and the Middle East. Data from India are limited to case reports. We performed an analysis to determine the prevalence of CMMRD in the Indian population. Materials and Methods All children aged less than 18 years with a diagnosis of CMMRD from various centers in India were included. CMMRD confirmed using genetic, molecular, and clinical criteria by an international consensus was included in the analysis. Literature search and data submitted by individual centers were reviewed. Results The analysis revealed that 22 children had genetically confirmed CMMRD. The median age of the cohort was 6.5 years, with a male predominance (male:female, 2:1). The classical phenotype of café-au-lait macules was observed in 72.7 % of subjects. The most common pathological variant was found in the PMS2 gene, which accounted for 77.3 % of children. Hematological malignancy (T cell acute lymphoblastic leukemia) was the most common primary malignancy in our study that occurred at a median age of 5 years (interquartile range 4–6 years) followed by brain tumors. The age at initial presentation for CMMRD with mutations in MSH2, MSH6, and PMS2 was 5.4, 4, and 7.5 years, respectively. Conclusion The diagnosis of CMMRD requires a high index of suspicion for the early diagnosis, management, surveillance, counseling, and testing of family members. The awareness about CMMRD in clinicians is important so that diagnosis is made early, and a second malignancy is detected and treated early. The need for an Indian consortium to determine the actual burden of the disease, genetic characteristics, and course of illness in our country has been emphasized.

Therapeutic implications of homologous repair deficiency testing in patients with prostate cancer (Part 2 of 2).

Unfortunately, not all metastatic castration-resistant prostate cancer (mCRPC) patients receive available life-prolonging systemic therapies, emphasizing the need to optimize mCRPC treatment selections. Better guidelines are necessary to determine genetic testing for prostate cancer. In this two-part expert opinion-based guide, we provide an expert consensus opinion on the utilization of germline and somatic testing to detect HRR alterations in patients with mCRPC. This guide was developed by a multidisciplinary expert panel that convened in 2023-2024, including representatives from medical oncology, urology, radiation oncology, pathology, medical genomics, and basic science. In this second part, we highlight how genetic testing can lead to improved, life-prolonging mCRPC therapeutic strategies based on a review of the recent phase III trials and subsequent regulatory approvals for PARP inhibitors in mCRPC.

Targeted Therapies in Pancreatic Cancer: A New Era of Precision Medicine.

Pancreatic ductal adenocarcinoma (PDAC), a leading cause of cancer mortality in the United States, presents significant treatment challenges due to its late diagnosis and poor prognosis. Despite advances, the five-year survival rates remain dismally low, with only a fraction of patients eligible for potentially curative surgical interventions. This review aims to comprehensively examine the current landscape of targeted therapies in PDAC, focusing on recent developments in precision medicine approaches. We explore various molecular targets, including KRAS mutations, DNA damage repair deficiencies, mismatch repair pathway alterations, and rare genetic fusions. The review discusses emerging therapies, such as PARP inhibitors, immune checkpoint inhibitors, and novel targeted agents, like RET and NTRK inhibitors. We analyze the results of key clinical trials and highlight the potential of these targeted approaches in specific patient subgroups. Recent developments in PDAC research have emphasized precision oncology, facilitated by next-generation sequencing and the identification of genetic and epigenetic alterations. This approach tailors treatments to individual genetic profiles, improving outcomes and reducing side effects. Significant strides have been made in classifying PDAC into various subtypes, enhancing therapeutic precision. The identification of specific mutations in genes like KRAS, along with advancements in targeted therapies, including small molecule inhibitors, offers new hope. Furthermore, emerging therapies targeting DNA repair pathways and immunotherapeutic strategies also show promising results. As research evolves, integrating these targeted therapies with conventional treatments might improve survival rates and quality of life for PDAC patients, underscoring the shift towards a more personalized treatment paradigm.

Neoadjuvant immunotherapy for dMMR and pMMR colorectal cancers: therapeutic strategies and putative biomarkers of response.

Approximately 15% of locally advanced colorectal cancers (CRC) have DNA mismatch repair deficiency (dMMR), resulting in high microsatellite instability and a high tumour mutational burden. These cancers are frequently sensitive to therapy with immune-checkpoint inhibitors (ICIs) in the metastatic setting. This sensitivity seems to be even more pronounced in locally advanced disease, and organ preservation has become a realistic aim in ongoing clinical trials involving patients with dMMR rectal cancer. By contrast, metastatic CRCs with proficient DNA mismatch repair (pMMR) are generally resistant to ICIs, although a proportion of locally advanced pMMR tumours seem to have a high degree of sensitivity to ICIs. In this Review, we describe the current and emerging clinical evidence supporting the use of neoadjuvant ICIs in patients with dMMR and pMMR CRC, and the potential advantages (based on a biological rationale) of such an approach. We discuss how neoadjuvant 'window-of-opportunity' trials are being leveraged to progress biomarker discovery and we provide an overview of potential predictive biomarkers of response to ICIs, exploring the challenges faced when evaluating such biomarkers in biopsy-derived samples. Lastly, we describe how these discoveries might be used to drive a rational approach to trialling novel immunotherapeutic strategies in patients with pMMR CRC, with the ultimate aim of disease eradication and the generation of long-term immunosurveillance.

Molecular mechanism of PARP inhibitor resistance.

Poly (ADP-ribose) polymerases (PARP) inhibitors (PARPi) are the first-approved anticancer drug designed to exploit synthetic lethality. PARPi selectively kill cancer cells with homologous recombination repair deficiency (HRD), as a result, PARPi are widely employed to treated BRCA1/2-mutant ovarian, breast, pancreatic and prostate cancers. Currently, four PARPi including Olaparib, Rucaparib, Niraparib, and Talazoparib have been developed and greatly improved clinical outcomes in cancer patients. However, accumulating evidences suggest that required or de novo resistance emerged. In this review, we discuss the molecular mechanisms leading to PARPi resistances and review the potential strategies to overcome PARPi resistance.

Abstract C010: Integrating germline and somatic data to resolve variants of uncertain significance (VUS) in colorectal cancer (CRC) patients who self-identified as Hispanic/Latino

Abstract Germline and somatic genetic testing have become cornerstones for assessing patient risk and tailoring cancer treatment, respectively, relying on the ability to distinguish pathogenic from benign variants. Typically, clinical reporting from these tests is conducted independently, serving distinct clinical objectives and audiences. However, integrating the underlying genomic data from both germline and somatic tests can enhance interpretative clarity, particularly in resolving variants of unknown significance (VUS) that lack sufficient evidence to determine pathogenicity. This ambiguity is especially problematic for non-White populations and those of non-European ancestry, where VUSs are disproportionately found, thereby limiting the scope of precision medicine and perpetuating health disparities. To assess the potential utility of an integrated model, we examined a prospective cohort of 88 self-identified Hispanic patients with colorectal cancer (CRC), performing both germline and somatic genomic analyses. We found that at least one germline VUS was identified in 44% (39/88) of participants, compared to a frequently reported rate of below 15%. By integrating tumor transcriptome data, mutational signatures, and copy number variations with traditional germline testing, we aimed to clarify VUSs and identify driver mutations. Integrating data modalities of the tumor transcriptome, mutational signatures, and copy number variations alongside traditional germline testing can help clarify VUSs and identify driver mutations. We constructed a model whereby the assessment of VUSs was based on the putative functional impact on either the DNA mutational patterns or allelic expression observed in tumor RNA. Using our integrated model, we deemed the oncogene AXIN2 VUS of one participant was likely biologically significant due to mutant-allele specific expression observed in the tumor RNA. Furthermore, we showed that 26% (10/39) of participants harbored a VUS that was very likely benign based on the tumor mutational profile and RNA expression. These included variants associated with homologous recombination in PALB2 and BRCA2 as well as genes associated with DNA repair like MLH1, PMS2, POLE and POLD1. Among patients with VUSs in genes associated with homologous recombination deficiency (HRD), none exhibited HRD via copy number analyses. Conversely, of the six patients that did exhibit HRD, only one had a pathogenic variant in a gene associated with HRD (ATM). Additionally, we identified tumors with a DNA mismatch repair deficiency phenotype (high tumor mutational burden, high microsatellite instability, DNA mismatch repair deficiency mutational signature) but without a pathogenic variant in a Lynch syndrome-associated gene. Methylation analysis revealed hypermethylation of the MLH1 promoter in these cases, explaining the tumor phenotype. This finding indicates that our integrative method can accurately predict DNA mismatch repair deficiency even without a genetic alteration in a DNA mismatch repair gene. Citation Format: Jonathan Amzaleg, Julie O. Culve, Charité N. Ricker, Natalia Gutierrez, Yuxin Jin, Brigette Waldrup, Carmen Chaves, Lucia Enriquez, Joel Sanchez-Mendez, Daisy Hernandez, Bodour Salhia, Lourdes Baezconde-Garbanati, Mariana C. Stern, Enrique Velazquez Villarreal, John D. Carpten, Heinz-Joseph Lenz, David W. Craig. Integrating germline and somatic data to resolve variants of uncertain significance (VUS) in colorectal cancer (CRC) patients who self-identified as Hispanic/Latino [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr C010.

Comprehensive analysis of constitutional mismatch repair deficiency-associated non-Hodgkin lymphomas in a global cohort.

Constitutional mismatch repair deficiency syndrome (CMMRD) is a rare childhood cancer predisposition syndrome associated with a broad spectrum of malignancies, including non-Hodgkin lymphomas (NHL). Most patients die due to cancer before the age of 20years. Limited data exist on CMMRD-associated lymphomas and their outcome. We conducted a retrospective study including all CMMRD-associated NHL patients registered before 2020 in the European and North American databases or reported by members of the European Intergroup for Childhood Non-Hodgkin Lymphoma (EICNHL). Events considered to define event-free survival included relapse/progression, second malignancy (SML), or death, whichever occurred first. The analysis included 74 patients, with 20 having multiple metachronous NHL. The median age at diagnosis was 9.4years. Previous malignancies were reported in 36% of the patients, café au lait spots in 96%, and consanguinity in 54%. The initial lymphoma subtypes were 53 T-cell lymphoblastic lymphomas (T-LBL), four B-lymphoblastic lymphomas, and 17 mature B-cell non-Hodgkin lymphoma (B-NHL). All patients were treated with curative intent, with current chemotherapy regimens adapted to their subtype. The median follow-up was 8.7years. After the first lymphoma, the 5-year event-free and overall survival rates were, respectively, 23.5% [95% confidence interval (CI): 14.9-35.1] and 61.5% [95% CI: 49.6-72.1]. The 5-year cumulative risk of progression/relapse, SML or death as a first event was 20.8%, 52.9%, and 2.7%. Standard treatments for sporadic NHL are effective in most CMMRD-associated NHL cases, but multiple malignancies, including lymphomas, impair prognosis. Future strategies should evaluate the potential of less genotoxic therapies, including immunotherapy, in preventing SMLs while maintaining effective control of NHL.

Ipilimumab with nivolumab in molecularly selected patients with castration-resistant prostate cancer: primary analysis of the phase II INSPIRE trial

Metastatic castration-resistant prostate cancer (mCRPC) typically exhibits resistance to immune checkpoint inhibitors (ICIs). However, a subset of mCRPC patients displays a more immunogenic profile. This study examines efficacy and safety of dual ICI therapy in molecularly selected mCRPC. This single-arm, phase II trial included 69 molecularly selected mCRPC patients with mismatch repair deficiency (dMMR), non-synonymous tumour mutational burden ≥7.1 muts/Mb (hTMB), a BRCA2 mutation (BRCAm), or biallelic CDK12 inactivation (CDK12i). Efficacy was assessed in ICI-naïve patients (cohort A) with RECIST 1.1 (A1) and Prostate Cancer Working Group 3 (A2) measurable disease. Safety was evaluated in cohorts A and B (prior ICI monotherapy). Treatment included nivolumab 3 mg/kg and ipilimumab 1 mg/kg every 3 weeks for four cycles, followed by nivolumab 480 mg every 4 weeks for up to 1 year. The primary endpoint was disease control rate beyond 6 months (DCR > 6), aiming to surpass a DCR > 6 of 22%. Patients initiated treatment between January 2021 and February 2024. Cohort A included 65 patients. Of these, 21 had dMMR (32%), 8 had hTMB (12%), 20 had BRCAm (31%), and 16 had CDK12i (25%). DCR > 6 was achieved in 38% of patients [95% confidence interval (CI) 27% to 51%], and was highest in dMMR (81%), followed by hTMB (25%), CDK12i (19%), and BRCAm (15%). Objective response rate in cohort A was 38% (95% CI 22% to 55%) and 47% (95% CI 34% to 60%) exhibited a 50% decline in prostate-specific antigen levels. Median progression-free survival (PFS) was 4.0 months (95% CI 3.5-12.0 months) in cohort A, and 32.7 months (95% CI 21.8 months-not reached) in dMMR patients. Treatment-related adverse events (TRAEs) led to permanent discontinuation in 14 of 69 patients (20%). Grade ≥3 TRAEs occurred in 48% of patients, with diarrhoea and elevated transaminases each in 10%. There was one treatment-related death due to a bowel perforation and a second following euthanasia after grade 4 toxicity. This trial of dual ICIs in molecularly selected mCRPC met its primary endpoint, showing DCR > 6 in 38% of patients. Dual ICIs exhibited modest responses in the hTMB, BRCAm, and CDK12i subgroups, but demonstrated exceptional efficacy in dMMR.

Top advances of the year: Immunotherapy in endometrial cancer.

In the past year, notable advances were achieved toward improving oncological outcomes in patients with advanced and recurrent endometrial cancer because of reporting of high-level results of several phase 3 clinical trial combining an immune checkpoint inhibitor with chemotherapy in the first-line setting. For the first time, patients with recurrent or advanced endometrial cancer have options for treatment that are superior to traditional chemotherapy alone. What remains to be determined is population specificity of these recommendations. All four major studies were in agreement that patients with endometrial cancer with deficient mismatch repair markedly benefited from addition of an immune checkpoint inhibitor for progression-free survival; some showed preliminary results demonstrating a potential overall survival. Molecular characterization details are needed to determine if and which patients with tumors that are mismatch proficient should receive this new combination approach. PLAIN LANGUAGE SUMMARY: Combining an immune checkpoint inhibitor with chemotherapy in the first-line setting treatment of patients with advanced endometrial cancer improved progression-free survival, especially in patients with mismatch repair deficiency. Improving patient selection with potential biomarkers of sensitivity and biomarkers of resistance is key in developing the next clinical trials and will assist in directing therapy to the correct patients and minimize toxicity.

Neoadjuvant nivolumab and relatlimab in locally advanced MMR-deficient colon cancer: a phase 2 trial.

Mismatch repair deficiency (dMMR) is found in approximately 15% of non-metastatic colon cancers (CCs) and is characterized by a defective DNA mismatch repair system, resulting in hypermutated and highly immunogenic tumors. Although patients with dMMR CC have limited benefit from chemotherapy, these tumors have been shown to respond exceptionally well to neoadjuvant anti-PD-1 plus anti-CTLA-4, with high rates of pathologic responses. Here, based on data from melanoma studies, we postulated a high efficacy and favorable toxicity profile of anti-PD-1 plus anti-LAG-3. In the NICHE-3 study, a total of 59 patients with locally advanced dMMR CC were treated with two 4-weekly cycles of nivolumab (480 mg) plus relatlimab (480 mg) before surgery. Pathologic response was observed in 57 of 59 (97%; 95% confidence interval (CI): 88-100%) patients, meeting the primary endpoint. Responses included 54 (92%; 95% CI: 81-97%) major pathologic responses (≤10% residual viable tumor) and 40 (68%; 95% CI: 54-79%) pathologic complete responses. With a median follow-up of 8 months (range, 2-19), one patient had recurrence of disease. The treatment displayed an acceptable safety profile, with all-grade and grade 3-4 immune-related adverse events (irAEs) occurring in 80% and 10% of patients, respectively. The most common irAEs were infusion-related reactions (29%), thyroid dysfunction (22%) and fatigue (20%). In conclusion, our results show that neoadjuvant nivolumab/relatlimab induces high rates of pathologic responses and that further investigation of this treatment in larger studies is warranted. These data add to the body of evidence in support of neoadjuvant immunotherapy regimens in dMMR CC. ClinicalTrials.gov identifier: NCT03026140 .

Datopotamab-deruxtecan in early-stage breast cancer: the sequential multiple assignment randomized I-SPY2.2 phase 2 trial.

Among the goals of patient-centric care are the advancement of effective personalized treatment, while minimizing toxicity. The phase 2 I-SPY2.2 trial uses a neoadjuvant sequential therapy approach in breast cancer to further these goals, testing promising new agents while optimizing individual outcomes. Here we tested datopotamab-deruxtecan (Dato-DXd) in the I-SPY2.2 trial for patients with high-risk stage 2/3 breast cancer. I-SPY2.2 uses a sequential multiple assignment randomization trial design that includes three sequential blocks of biologically targeted neoadjuvant treatment: the experimental agent(s) (block A), a taxane-based regimen tailored to the tumor subtype (block B) and doxorubicin-cyclophosphamide (block C). Patients are randomized into arms consisting of different investigational block A treatments. Algorithms based on magnetic resonance imaging and core biopsy guide treatment redirection after each block, including the option of early surgical resection in patients predicted to have a high likelihood of pathological complete response, the primary endpoint. There are two primary efficacy analyses: after block A and across all blocks for the six prespecified breast cancer subtypes (defined by clinical hormone receptor/human epidermal growth factor receptor 2 (HER2) status and/or the response-predictive subtypes). We report results of 103 patients treated with Dato-DXd. While Dato-DXd did not meet the prespecified threshold for success (graduation) after block A in any subtype, the treatment strategy across all blocks graduated in the hormone receptor-negative HER2-Immune-DNA repair deficiency- subtype with an estimated pathological complete response rate of 41%. No new toxicities were observed, with stomatitis and ocular events occurring at low grades. Dato-DXd was particularly active in the hormone receptor-negative/HER2-Immune-DNA repair deficiency- signature, warranting further investigation, and was safe in other subtypes in patients who followed the treatment strategy. ClinicalTrials.gov registration: NCT01042379 .

Tumour immune characterisation of primary triple-negative breast cancer using automated image quantification of immunohistochemistry-stained immune cells

The tumour immune microenvironment (TIME) in breast cancer is acknowledged with an increasing role in treatment response and prognosis. With a growing number of immune markers analysed, digital image analysis may facilitate broader TIME understanding, even in single-plex IHC data. To facilitate analyses of the latter an open-source image analysis pipeline, Tissue microarray MArker Quantification (TMArQ), was developed and applied to single-plex stainings for p53, CD3, CD4, CD8, CD20, CD68, FOXP3, and PD-L1 (SP142 antibody) in a 218-patient triple negative breast cancer (TNBC) cohort with complementary pathology scorings, clinicopathological, whole genome sequencing, and RNA-sequencing data. TMArQ’s cell counts for analysed immune markers were on par with results from alternative methods and consistent with both estimates from human pathology review, different quantifications and classifications derived from RNA-sequencing as well as known prognostic patterns of immune response in TNBC. The digital cell counts demonstrated how immune markers are coexpressed in the TIME when considering TNBC molecular subtypes and DNA repair deficiency, and how combination of immune status with DNA repair deficiency status can improve the prognostic stratification in chemotherapy treated patients. These results underscore the value and potential of integrating TIME and specific tumour intrinsic alterations/phenotypes for the molecular understanding of TNBC.

Clinico-Pathological Characteristics of Endometrial Carcinoma with Mismatch Repair Deficiency

Background: Endometrial carcinoma (EC) is a common gynecologic malignancy with significant implications for women's health. Mismatch repair deficiency (MMRd) has emerged as a critical factor influencing the pathogenesis and prognosis of EC. This study aims to investigate the clinicopathologic characteristics of MMRd EC in a Bangladeshi cohort. Methods: This cross-sectional observational study was conducted at the Department of Gynecological Oncology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, from March 2022 to February 2023. A total of 49 patients with histologically confirmed EC were included. Data were collected through a semi-structured questionnaire and patient records. Results: Among the 49 patients, 67.35% (n=33) were MMR proficient, while 32.65% (n=16) were MMR deficient. The mean age was 55 years for MMR proficient and 55.6 years for MMR deficient patients. Hypertension was present in 69.70% of MMR proficient and 75% of MMR deficient patients, while diabetes mellitus affected 54.55% of MMR proficient and 62.50% of MMR deficient patients. MMRd patients showed higher rates of adnexal involvement (37.50% vs. 6.06%, p=0.010) and metastasis (37.50% vs. 9.09%, p=0.024). Multivariate logistic regression identified advanced FIGO stage (III & IV) as a significant predictor of MMR deficiency (adjusted OR 4.274, 95% CI: 1.691-15.515, p=0.025). Conclusion: MMRd in endometrial carcinoma is associated with more aggressive tumor features and poorer prognostic indicators. Routine evaluation of MMR status is crucial for effective prognosis and treatment planning. Addressing socioeconomic disparities and integrating targeted therapeutic strategies can improve management and outcomes for patients with MMRd endometrial carcinoma in diverse populations.

Targeting GPX4-mediated ferroptosis protection sensitizes BRCA1-deficient cancer cells to PARP inhibitors

BRCA1 is one of the most frequently-mutated tumor suppressor genes in ovarian and breast cancers. Loss of BRCA1 triggers homologous recombination (HR) repair deficiency, consequently leading to genomic instability and PARP inhibitors (PARPi)-associated synthetic lethality. Although, the roles of BRCA1 in DNA repair and replication have been extensively investigated, its tumor suppressive functions beyond genome safeguard remain poorly understood. Here, we report that BRCA1 promotes ferroptosis susceptibility through catalyzing K6-linked polyubiquitination of GPX4 and subsequently accelerating GPX4 degradation. Depletion of BRCA1 induces ferroptosis resistance in ovarian cancer cells due to elevated GPX4 protein, and silence of GPX4 significantly suppresses the growth of BRCA1-deficient ovarian cancer xenografts. Importantly, we found that PARPi triggers ferroptosis in ovarian cancer cells, inhibition of GPX4 markedly increase PARPi-induced ferroptosis in BRCA1-deficient ovarian cancer cells. Combined treatment of GPX4 inhibitor and PARPi produces synergistic anti-tumor efficacy in BRCA1-deficient ovarian cancer cells, patient derived organoid (PDO) and xenografts. Thus, our study uncovers a novel mechanism via which BRCA1 exerts tumor suppressive function through regulating ferroptosis, and demonstrates the potential of GPX4 as a therapeutic target for BRCA1-mutant cancers.

Prevalence of germline variants in Brazilian pancreatic carcinoma patients

We evaluated the prevalence of pathogenic/likely pathogenic germline variants (PGV) in Brazilian pancreatic adenocarcinoma (PC) patients, that represent a multiethnic population, in a cross-sectional study. We included 192 PC patients unselected for family history of cancer. We evaluated a panel of 113 cancer genes, through genomic DNA sequencing and 46 ancestry-informative markers, through multiplex PCR. The median age was 61 years; 63.5% of the patients presented disease clinical stages III or IV; 8.3% reported personal history of cancer; 4.7% and 16.1% reported first-degree relatives with PC or breast and/or prostate cancer, respectively. Although the main ancestry was European, there was considerable genetic composition admixture. Twelve patients (6.25%) were PGV carriers in PC predisposition genes (ATM, BRCA1, BRCA2, CDKN2A, MSH2, PALB2) and another 25 (13.0%) were PGV carriers in genes with a limited association or not previously associated with PC (ACD, BLM, BRIP1, CHEK2, ERCC4, FANCA, FANCE, FANCM, GALNT12, MITF, MRE11, MUTYH, POLE, RAD51B, RAD51C, RECQL4, SDHA, TERF2IP). The most frequently affected genes were CHEK2, ATM and FANC. In tumor samples from PGV carriers in ACD, BRIP1, MRE11, POLE, SDHA, TERF2IP, which were examined through exome sequencing, the main single base substitutions (SBS) mutational signature was SBS1+5+18, probably associated with age, tobacco smoking and reactive oxygen species. SBS3 associated with homologous repair deficiency was also represented, but on a lower scale. There was no difference in the frequency of PGV carriers between: (a) patients with or without first-degree relatives with cancer; and (b) patients with admixed ancestry versus those with predominantly European ancestry. Furthermore, there was no difference in overall survival between PGV carriers and non-carriers. Therefore, genetic testing should be offered to all Brazilian pancreatic cancer patients, regardless of their ancestry. Genes with limited or previously unrecognized associations with pancreatic cancer should be further investigated to clarify their role in cancer risk.

Clinical status and future prospects of neoadjuvant immunotherapy for localized mismatch repair-deficient cancers: a review.

Frameshift mutations accumulate in cancers related to mismatch repair deficiency (dMMR), which has the potential to produce various neoantigens, representing a distinct subset of cancers that respond considerably to immunotherapy. In recent years, robust evidence has supported the first-line application of immunotherapy for patients with metastatic dMMR cancers, which provoked extensive investigations of the feasibility and efficacy of immunotherapy in up-front settings, including neoadjuvant therapy. Several completed trials with small sample sizes suggested that neoadjuvant immunotherapy can achieve an impressively high complete response rate, for the first time offering the potential of systemic therapy to cure cancer without the need for surgical resection. However, a difficult dilemma emerges: clinicians are now facing a selection between the standard of care with good evidence for proficient MMR but suboptimal for dMMR cancers and the emerging immunotherapy with promising results but only based on a limited number of patients with shorter duration of follow-up. This review aims to provide a comprehensive summary of the biological rationale and clinical status of neoadjuvant immunotherapy in patients with dMMR cancers. Furthermore, I elaborate on particular issues that must be taken into consideration for further advancement in the field.

Single-cell AI-based detection and prognostic and predictive value of DNA mismatch repair deficiency in colorectal cancer

Testing for DNA mismatch repair deficiency (MMRd) is recommended for all colorectal cancers (CRCs). Automating this would enable precision medicine, particularly if providing information on etiology not captured by deep learning (DL) methods. We present AIMMeR, an AI-based method for determination of mismatch repair (MMR) protein expression at a single-cell level in routine pathology samples. AIMMeR shows an area under the receiver-operator curve (AUROC) of 0.98, and specificity of ≥75% at 98% sensitivity against pathologist ground truth in stage II/III in two trial cohorts, with positive predictive value of ≥98% for the commonest pattern of somatic MMRd. Lower agreement with microsatellite instability (MSI) testing (AUROC 0.86) reflects discordance between MMR and MSI PCR rather than AIMMeR misclassification. Analysis of the SCOT trial confirms MMRd prognostic value in oxaliplatin-treated patients; while MMRd does not predict differential benefit of chemotherapy duration, it correlates with difference in relapse by regimen (PInteraction= 0.04). AIMMeR may help reduce pathologist workload and streamline diagnostics in CRC.

Impact of molecular and histopathological findings on FIGO 2009 stage I endometrial cancer: Transition to FIGO 2023 staging system.

This study aims to investigate the impact of integrating molecular and histopathological findings into the revised International Federation of Gynecology and Obstetrics (FIGO) 2023 staging system on patients initially diagnosed with stage I endometrial cancer (EC) according to the FIGO 2009 criteria. A cohort of 197 EC patients, initially classified as stage I under FIGO 2009, underwent restaging based on the updated FIGO 2023 criteria. The patients' molecular and histopathological characteristics were documented, and their impact on upstaging was analyzed. Molecular profiling was conducted for 81.2% (160/197) of the patients, revealing that 55.3% (109/197) were classified as non-specific molecular profile, 14.7% (29/197) as mismatch repair deficiency, 11.2% (22/197) as p53 abnormality (p53abn), and 18.8% (37/197) as unknown. Upstaging was identified in 26.9% (43/160) of the 160 patients with known molecular profiles. Among the upstaged patients, 51.2% experienced upstaging due to p53 abnormality, 20.9% due to substantial lymphovascular space invasion (LVSI), 20.9% due to aggressive histological types, and 6.9% due to high grade. The introduction of the molecular profile into the revised FIGO 2023 staging system for stage I EC has led to notable changes in the staging of approximately one-fifth of patients. While p53 abnormalities have emerged as the most influential factor contributing to the upstaging, LVSI and aggressive histological types also represent significant contributing factors.