Frequency of high‐risk hormone receptor‐positive breast cancer patients was much higher in Japanese breast cancer patients with germline BRCA1/2 mutations than in sporadic breast cancer patients. Issue 2 (30th December 2020) - Ide, Yoshimi; Liu, Lei; Miura, Sakiko; Inuzuka, Mayuko; Akashi‐Tanaka, Sadako; Sawada, Terumasa; Nakamura, Seigo