Among these tumors, 460 (81.6%) were invasive ductal carcinomas (IDCs) of nonspecific type, 79 (14%) were invasive lobular carcinomas (ILCs), and the majority were positive for estrogen receptor (ER) and progesterone receptor (PR) (91.1% and 78.9%, respectively). Here, ESR1 is linked to invasive lobular breast carcinoma.