Immunohistochemical analysis revealed that benign tumors had a similar expression of ER, PR, fHER2, Ki-67 and CK5/6 to the aforementioned benign non-neoplastic lesions, with 67% of lesions showing ER positive status, with an fHER2 and a CK 5/6 negative status. Here, ESR1 is linked to benign neoplasm.