In accordance with previous data revealing that a cooperative interaction between ERα66 and IR transduction pathways plays a critical role in breast carcinogenesis, tumor cell proliferation, differentiation and survival,40, 41, 42 we demonstrated that regulatory crosstalk occurs between ERα46 and IR upon E2 and insulin stimulation for BCAHC‐1 cell growth and pulmonary metastasis. Here, INS is linked to neoplasm.