[Prostate cancer with BRCA2 pathogenic mutation: a clinicopathological analysis]

Objective: To analyze the clinicopathological features of prostate cancers with BRCA2 pathogenic mutations, and the association between BRCA2 pathogenic mutation and clinicopathological characteristics. Patient survivals were also examined. Methods: Clinicopathological data of 249 prostate cancer patients who underwent genetic testing in West China Hospital of Sichuan University, Chengdu, China from June 2014 to August 2021 were collected. A retrospective analysis of histopathological morphology, clinicopathological characteristics, and patient survivals was conducted. Results: The genetic testing in the 249 prostate cancer patients showed a pathogenic mutation of DNA damage repair gene (DRG) in 73 cases (73/249, 29.3%), including 22 cases (8.8%) with BRCA2 pathogenic mutation and 51 cases with pathogenic mutations of other DRG. Among the 22 patients with BRCA2 pathogenic mutation, 14 patients (5.6%) harbored germline mutations and 8 patients (3.2%) somatic mutations. Their ages ranged from 48 to 91 years, with a median of 67 years. Seventeen patients (77.3%) had distant metastasis, including 16 cases with bone metastasis and 1 case with multiple metastases. Thirteen patients (59.1%) were castration-resistant prostate cancer. The histological type was mainly classical prostatic acinar adenocarcinoma, including 16 cases (72.7%) with intraductal carcinoma of the prostate (IDC-P). Six cases (27.3%) showed focal neuroendocrine differentiation. Perineural/vascular invasion and extraprostatic extension were seen in 11 cases (50.0%) and 8 cases (36.4%), respectively. The Gleason scores of 19 patients (86.4%) were≥8. IDC-P was more commonly found in patients with BRCA2 germline pathogenic mutation than those with BRCA2 somatic pathogenic mutation, other DRG pathogenic mutation or no-DRG pathogenic mutation (P=0.002). With a total follow-up time of 189 months, the median overall survival (OS) was 132.3 months. Patients with DRG pathogenic mutation had shorter OS than those with no-DRG pathogenic mutation (P=0.040). The OS of patients with BRCA2 germline pathogenic mutation did not significantly differ from that of patients with BRCA2 somatic pathogenic mutation, other DRG pathogenic mutation or no-DRG pathogenic mutation (P=0.216). Conclusions: The presence of BRCA2 gene pathogenic mutation is common in the prostate cancers with high Gleason grade, advanced clinical stage, and castration resistance. IDC-P is more commonly noted in cases with BRCA2 germline pathogenic mutation than those without. Patients with DRG pathogenic mutation have shorter OS than those with no-DRG pathogenic mutation, but there is no significant association between BRCA2 pathogenic mutations and OS.