Our previous work demonstrated that mammary tumors induced by overexpression of IGF-IR in MTB-IGFIR transgenic mice, also know as primary mammary tumors or PMTs, had features of luminal tumors such as an epithelial morphology and E-cadherin expression, however, these tumors clustered most closely with human basal-like breast tumors [39]. Here, IGF1R is linked to breast cancer.