Comprehensive analysis of germline drivers in endometrial cancer

Pathogenic germline variants among women with uterine cancer by ancestry: A commercial laboratory collaborative research registry study

OBJECTIVE

Uterine cancer (UC) is the most common gynecologic cancer in the United States, and 5-15 % of patients harbor a germline pathogenic variant (gPV) in a cancer predisposition gene. This study aims to characterize the germline landscape of patients with UC by self-identified ancestry.

METHODS

Patients with UC who received germline testing were identified from the publicly available Myriad Collaborative Research Registry. Rates of gPVs were calculated, overall and by self-reported ancestry, with a focus on genes associated with UC, including Lynch syndrome (LS) and homologous recombination-related (HR) genes.

RESULTS

Among 35,310 patients with UC, 23,081 (65.4 %) identified as White, 3683 (10.4 %) as Hispanic, 2132 (6.0 %) as Black, 1244 (3.5 %) as Ashkenazi Jewish (AJ), 1093 (3.1 %) as Asian, and 7550 (21.4 %) as Other. Overall, 5141 (14.6 %) patients had a gPV, with highest rates among White (15.5 %) and Asian (17.8 %) compared to Black (10.4 %) and Hispanic (11.6 %) patients, p < 0.0001. LS gPVs were observed in 3155 (8.9 %) patients and was most prevalent in Asian women (12.9 %), particularly MLH1 and MSH2-associated LS. HR-related gPVs were found in 1066 (3.0 %) patients overall and were most common in AJ (4.1 %) and Black (4.0 %) patients, with high rates of BRCA1/2 gPVs in AJ patients and non-BRCA HR-related gPVs in Black patients.

CONCLUSIONS

Of the over 35,000 patients with UC, 14.5 % had a gPV identified, supporting consideration of universal germline testing in endometrial cancer given high actionability. We observed heterogeneity in gPVs by self-reported ancestry with Black and Hispanic patients having the lowest rates, potentially contributing to disparities in UC.

Endometrial carcinomas with ambiguous histology often harbor TP53 mutations

The objective of the present study was to characterize the molecular features of endometrial carcinomas with ambiguous histology. Eighteen carcinomas that could not be conclusively typed based on morphology and immunohistochemistry underwent analysis of mismatch repair (MMR) status, microsatellite status, and whole-exome sequencing. None of the tumors had pathogenic POLE mutation. Twelve tumors (67%) were microsatellite stable, and 6 (33%) had microsatellite instability. Fourteen tumors (78%) harbored TP53 mutations, and 2 (11%) had mutations in MMR genes. Eleven carcinomas (61%) were classified as copy number high and 7 (39%) as MSI-hypermutated, the latter including 3 tumors with TP53 mutation who concomitantly had MSI or mutation in a MMR gene. Other mutations that were found in > 1 tumor affected MUC16 (7 tumors), PIK3CA (6 tumors), PPP2R1A (6 tumors), ARID1A (5 tumors), PTEN (5 tumors), FAT1 (4 tumors), FAT4 (3 tumors), BRCA2 (2 tumors), ERBB2 (2 tumors), FBXW7 (2 tumors), MET (2 tumors), MTOR (2 tumors), JAK1 (2 tumors), and CSMD3 (2 tumors). At the last follow-up (median = 68.6 months), 8 patients had no evidence of disease, 1 patient was alive with disease, 8 patients were dead of disease, and 1 patient died of other cause. In conclusion, based on this series, the molecular landscape of endometrial carcinomas with ambiguous histology is dominated by TP53 mutations and the absence of POLE mutations, with heterogeneous molecular profile with respect to other genes. A high proportion of these tumors is clinically aggressive.

Optimizing Mainstreaming of Genetic Testing in Parallel With Ovarian and Endometrial Cancer Tumor Testing: How Do We Maximize Our Impact?

PURPOSE

Although germline genetic testing (GT) is recommended for all patients with ovarian cancer (OC) and some patients with endometrial cancer (EC), uptake remains low with multiple barriers. Our center performs GT in parallel with somatic testing via a targeted sequencing assay (MSK-IMPACT) and initiates testing in oncology clinics (mainstreaming). We sought to optimize our GT processes for OC/EC.

METHODS

We performed a quality improvement study to evaluate our GT processes within gynecologic surgery/medical oncology clinics. All eligible patients with newly diagnosed OC/EC were identified for GT and tracked in a REDCap database. Clinical data and GT rates were collected by the study team, who reviewed data for qualitative themes.

RESULTS

From February 2023 to April 2023, we identified 116 patients with newly diagnosed OC (n = 57) and EC (n = 59). Patients were mostly White (62%); English was the preferred language for 90%. GT was performed in 52 (91%) patients with OC (seven external, 45 MSK-IMPACT) and in 44 (75%) patients with EC (three external, 41 MSK-IMPACT). GT results were available within 3 months for 100% and 95% of patients with OC and EC, respectively. Reasons for not undergoing GT included being missed by the clinical team where there was no record that GT was recommended, feeling overwhelmed, financial and privacy concerns, and language barriers. In qualitative review, we found that resources were concentrated in the initial visit with little follow-up to encourage GT at subsequent points of care.

CONCLUSION

A mainstreaming approach that couples somatic and germline GT resulted in high testing rates in OC/EC; however, barriers were identified. Processes that encourage GT at multiple care points and allow self-directed, multilingual digital consenting should be piloted.

Endometrial Cancer in a Family With RAD51D Gene Mutation

RAD51 complex plays an important role in homologous recombination deficiency and germline mutations have a well-documented association with breast and tubo-ovarian carcinoma, as well as serous-type endometrial carcinoma. We report a family of French Canadian ancestry with a germline mutation in RAD51D and two sisters presenting with endometrial carcinoma, endometrioid-type. The risk factors for endometrial adenocarcinoma, endometrioid-type are discussed in the context of the RAD51-associated carcinomas described to date.

A tale of two pathways: Review of immune checkpoint inhibitors in DNA mismatch repair-deficient and microsatellite instability-high endometrial cancers

The DNA mismatch repair (MMR) pathway is critical for correcting DNA mismatches generated during DNA replication. MMR-deficiency (MMR-D) leads to microsatellite instability (MSI) associated with an increased mutation rate, driving cancer development. This is particularly relevant in endometrial cancer (EC) as 25%-30% of tumors are of MMR-D/MSI-high (MSI-H) phenotype. Comprehensive assessment using immunohistochemistry (IHC) and sequencing-based techniques are necessary to fully evaluate ECs given the importance of molecular subtyping in staging and prognosis. This also influences treatment selection as clinical trials have demonstrated survival benefits for immune checkpoint inhibitors (ICIs) alone and in combination with chemotherapy for MMR-D/MSI-H EC patients in various treatment settings. As a portion of MMR-D/MSI-H ECs are driven by Lynch syndrome, an inherited cancer predisposition syndrome that is also associated with colorectal cancer, this molecular subtype also prompts germline assessment that can affect at-risk family members. Additionally, heterogeneity in the tumor immune microenvironment and tumor mutation burden (TMB) have been described by MMR mechanism, meaning MLH1 promoter hypermethylation versus germline/somatic MMR gene mutation, and this may affect response to ICI therapies. Variations by ancestry in prevalence and mechanism of MMR-D/MSI-H tumors have also been reported and may influence health disparities given observed differences in tumors of Black compared to White patients which may affect ICI eligibility. These observations highlight the need for additional prospective studies to evaluate the nuances regarding MMR-D heterogeneity as well as markers of resistance to inform future trials of combination therapies to further improve outcomes for patients with EC.

Pathogenic germline variants in patients with endometrial cancer of diverse ancestry

BACKGROUND

Racial disparities in outcomes exist in endometrial cancer (EC). The contribution of ancestry-based variations in germline pathogenic variants (gPVs) is unknown.

METHODS

Germline assessment of ≥76 cancer predisposition genes was performed in patients with EC undergoing tumor-normal Memorial Sloan Kettering Cancer Center Integrated Mutation Profiling of Actionable Cancer Targets sequencing from January 1, 2015 through June 30, 2021. Self-reported race/ethnicity and Ashkenazi Jewish ancestry data classified patients into groups. Genetic ancestry was inferred from Memorial Sloan Kettering Cancer Center Integrated Mutation Profiling of Actionable Cancer Targets. Rates of gPV and genetic counseling were compared by ancestry.

RESULTS

Among 1625 patients with EC, 216 (13%) had gPVs; 15 had >1 gPV. Rates of gPV varied by self-reported ancestry (Ashkenazi Jewish, 40/202 [20%]; Asian, 15/124 [12%]; Black/African American (AA), 12/171 [7.0%]; Hispanic, 15/124 [12%]; non-Hispanic (NH) White, 129/927 [14%]; missing, 5/77 [6.5%]; p = .009], with similar findings by genetic ancestry (p < .001). We observed a lower likelihood of gPVs in patients of Black/AA (odds ratio [OR], 0.44; 95% CI, 0.22-0.81) and African (AFR) ancestry (OR, 0.42; 95% CI, 0.18-0.85) and a higher likelihood in patients of Ashkenazi Jewish genetic ancestry (OR, 1.62; 95% CI; 1.11-2.34) compared with patients of non-Hispanic White/European ancestry, even after adjustment for age and molecular subtype. Somatic landscape influenced gPVs with lower rates of microsatellite instability-high tumors in patients of Black/AA and AFR ancestry. Among those with newly identified gPVs (n = 114), 102 (89%) were seen for genetic counseling, with lowest rates among Black/AA (75%) and AFR patients (67%).

CONCLUSIONS

In those with EC, gPV and genetic counseling varied by ancestry, with lowest rates among Black/AA and AFR patients, potentially contributing to disparities in outcomes given implications for treatment and cancer prevention.

PLAIN LANGUAGE SUMMARY

Black women with endometrial cancer do worse than White women, and there are many reasons for this disparity. Certain genetic changes from birth (mutations) can increase the risk of cancer, and it is unknown if rates of these changes are different between different ancestry groups. Genetic mutations in 1625 diverse women with endometrial cancer were studied and the lowest rates of mutations and genetic counseling were found in Black and African ancestry women. This could affect their treatment options as well as their families and may make disparities worse.

Modifiable Risk Factors and Risk of Colorectal and Endometrial Cancers in Lynch Syndrome: A Systematic Review and Meta-Analysis

PURPOSE

Lynch syndrome is the most common hereditary cause of colorectal and endometrial cancers. Modifiable risk factors, including obesity, physical activity, alcohol intake, and smoking, are well-established in sporadic cancers but are less studied in Lynch syndrome.

METHODS

Searches were conducted on MEDLINE, Embase, and Web of Science for cohort studies that investigated the association between modifiable risk factors and the risk of colorectal or endometrial cancer in people with Lynch syndrome. Adjusted hazard ratios (HRs) and 95% CIs for colorectal and endometrial cancers were pooled using a random effects model. The protocol was prospectively registered on PROSPERO (CRD 42022378462), and the meta-analysis was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Meta-Analysis of Observational Studies in Epidemiology reporting guidelines.

RESULTS

A total of 770 citations were reviewed. Eighteen studies were identified for qualitative synthesis, with seven colorectal cancer (CRC) studies eligible for meta-analysis. Obesity (HR, 2.38 [95% CI, 1.52 to 3.73]) was associated with increased CRC risk. There was no increased CRC risk associated with smoking (HR, 1.04 [95% CI, 0.82 to 1.32]) or alcohol intake (HR, 1.32 [95% CI, 0.97 to 1.81]). Type 2 diabetes mellitus (T2DM) and some dietary factors might increase risk of CRC although more studies are needed. In a qualitative synthesis of three endometrial cancer cohort studies, female hormonal risk factors and T2DM may affect the risk of endometrial cancer, but obesity was not associated with an increased risk.

CONCLUSION

Lifestyle recommendations related to weight and physical activity may also be relevant to cancer prevention for individuals with Lynch syndrome. Further high-quality prospective cohort studies, in particular, including endometrial cancer as an end point, are needed to inform evidence-based cancer prevention strategies in this high-risk population.

Targeting DNA Damage Repair and Immune Checkpoint Proteins for Optimizing the Treatment of Endometrial Cancer

The dependence of cancer cells on the DNA damage response (DDR) pathway for the repair of endogenous- or exogenous-factor-induced DNA damage has been extensively studied in various cancer types, including endometrial cancer (EC). Targeting one or more DNA damage repair protein with small molecules has shown encouraging treatment efficacy in preclinical and clinical models. However, the genes coding for DDR factors are rarely mutated in EC, limiting the utility of DDR inhibitors in this disease. In the current review, we recapitulate the functional role of the DNA repair system in the development and progression of cancer. Importantly, we discuss strategies that target DDR proteins, including PARP, CHK1 and WEE1, as monotherapies or in combination with cytotoxic agents in the treatment of EC and highlight the compounds currently being evaluated for their efficacy in EC in clinic. Recent studies indicate that the application of DNA damage agents in cancer cells leads to the activation of innate and adaptive immune responses; targeting immune checkpoint proteins could overcome the immune suppressive environment in tumors. We further summarize recently revolutionized immunotherapies that have been completed or are now being evaluated for their efficacy in advanced EC and propose future directions for the development of DDR-based cancer therapeutics in the treatment of EC.