Prevalence of pathogenic germline variants in DNA repair by race, age, and ethnicity in men with prostate cancer.
Mara, A; Zhu, J; Wu, Y; Callis, T; Yang, S; Esplin, ED; Nussbaum, RL; Zhang, T; McNamara, MA; Harrison, MR; George, DJ; Cooney, KA; Armstrong, AJ
Published in: Journal of Clinical Oncology
5062 Background: Patients with advanced prostate cancer (PC) frequently harbor pathogenic or likely pathogenic (P/LP) germline variants (GVs) in mismatch repair (MMR) and homologous repair (HR) enzymes which have clinical and treatment implications. However, whether the prevalence of such GVs differ by race, ethnicity, family history, or age is unknown in men with PC. Methods: This is a retrospective analysis of germline DNA from men with PC in the United States, tested by Invitae. Baseline characteristics including self-identified race, ethnicity, family history (FH), and age were recorded. Race and ethnicity were analyzed by 3 cohorts: non-Ashkenazi Caucasian Americans (CA), non-Ashkenazi African Americans (AA), and Ashkenazi Jewish Americans (AJ). Chi-square testing was performed to identify significant differences across these categories between the three cohorts, with respect to combined and individual pathogenic MMR (MSH2/6, MLH1, PMS2, and MUTYH) and HR genes (BRCA1/2, ATM, CHEK2, RAD51D, and PALB2). Results: 3057 men were included in the final analysis: 2248 (74%) men were CA, 229 (7%) were AA, and 210 (7%) were AJ. Of these, 2665 (87%) men had a FH of PC and 463 (15%) had a P/LP GV. In addition, 1068 (35%) were found to have a variant of uncertain significance, and 35 (1.6%) had the HOXB13 G84E variant. There were no significant differences in the overall prevalence of MMR (CA 1.5% vs AA 0.9% vs AJ 1.4%, p = 0.89) or HR genes (CA 7.8% vs AA 7.9% vs AJ 10.5%, p = 0.37) by race/ethnicity. With respect to individual genes, AJ had a higher prevalence of pathogenic BRCA1 alterations (AJ 3.3% vs CA 0.8% vs AA 1.7%, p = 0.0034) and CHEK2 alterations (AJ 4.3% vs CA 2.8% vs AA 0.4%, p = 0.02). There were no significant differences in the prevalence of individual or specific classes of GVs between those with or without a self-reported FH of prostate or breast/ovarian cancers. There was also no association between prevalence of HR genes and age at germline testing (p = 0.40). Conclusions: This national study found that the overall prevalence of pathogenic GVs in MMR and HR genes do not differ by race, ethnicity, or age at the time of testing, and suggests that all men with advanced prostate cancer should be offered germline testing.
