A first Japanese case of neuroendocrine prostate cancer accompanied by lung and brain metastasis with somatic and germline BRCA2 mutation

Germline mutations and copy number changes in DNA damage repair (DDR) genes such as BRCA2 are associated with aggressive forms of prostate cancer (PCa). Although the prevalence of BRCA2 variants in PCa is increasing in Japan, the genomic and biological implications in Japanese patients are unclear. An 81‐year‐old male presented with prostatic adenocarcinoma with neuroendocrine differentiation accompanied by metastatic lung nodule and brain metastases. Platinum‐based doublet chemotherapy combined with etoposide resulted in partial and complete remissions of brain and lung metastases, respectively. Next‐generation sequencing of biopsy and peripheral blood samples demonstrated a somatic BRCA2 mutation at c.7008‐2A>C and a germline mutation at p.E2877*. The patient's son had been diagnosed with breast cancer 2.5 years ago and was found to have the same germline BRCA2 mutation. BRCA2 mutation increases the risks of aggressive PCa and other cancer types in Japanese males. These forms may be highly responsive to platinum‐based chemotherapy.