Consistent with the fact that RAD51AP1 functions in both luminal ER-positive and triple-negative breast cancers, EMP3 affects RAD51 expression as well as DNA replication, DNA damage repair, and stem-like properties in both ER-positive MCF7 and triple-negative MDA-MB-231/HS578 cells. Here, EMP3 is linked to triple-negative breast carcinoma.