BRCA1/2 mutations are considered risk factors for ipsilateral breast cancer recurrence.20 Regarding HDGC caused by CDH1 germline mutation, multiple foci of signet ring cell carcinoma were detected in the stomach of individual patients.21,22 Prophylactic total gastrectomy is recommended for CDH1 mutation carriers because of the high cumulative incidence and the difficulty of early detection of HDGC by endoscopy.23 In this report, the intestinal type of GC, which is relatively easy to detect at an early stage by endoscopy, predominantly developed in the affected patients. Here, CDH1 is linked to breast carcinoma.