PTPRF and breast cancer: TNBC encompasses six heterogeneous subtypes of breast cancers, i.e., mesenchymal (M), mesenchymal stem-like (MSL), basal-like (BL1 and BL2), immunomodulatory (IM), and luminal androgen receptor- (LAR-) enriched tumors, each of which manifests distinct gene expression profiles and unique histological and molecular characteristics and responds differently to treatments [25].