However, co-culture of the luminal subtype with the BCAFs-conditioned medium revealed a transitional phenotypic switch of the luminal subtype to basal-like subtype BC through the PDGF-CC signaling axis, led to the reduction of the sensitivity to endocrine therapy, supporting the pro-tumorigenic role of CAFs in both subtypes. This evidence concerns the gene CXCR1 and breast cancer.