In essence, changes in IGF-1/IGF-1R signaling and the abnormal IGF-1/IGF-1R expression are related to cell proliferation, anti-apoptotic, epithelial to mesenchymal transition, and migratory effects in various neoplastic tumors (e.g., increased IGF-1R expression and high IGF-1 blood levels are associated with an augmented BC risk and shorter survival of patients with TNBC compared to those with ER-positive BC) [40]. This evidence concerns the gene ESR1 and breast cancer.