BRCA1 (breast cancer susceptibility gene 1) is a crucial protein that functions for HR repair.[26] BRCA1 could suppress error‐prone NHEJ repair of DSB and promote accurate HR repair of DSB.[27] Studies have shown that BRCA1 mutations lead to higher levels of DSB and are also associated with a variety of major diseases, such as epithelial ovarian cancer,[28] breast cancer,[29] and pancreatic cancer.[30] Given the importance of BRCA1 for HR repair, it is of significance to explore what might regulate BRCA1 abundance in human trophoblast cells. Here, BRCA1 is linked to breast cancer.