The pro‐angiogenic effect was due to FGF2 secretion, which was induced by cancer cell‐derived PDGF, and this was abrogated by pharmacological treatment to block stromal PDGFR signaling.107 After co‐transplantation of patient‐derived mammary CAFs and MCF7 breast carcinoma cells expressing activated HRas oncogene (MCF7‐HRas), CAFs induced the formation of tumors extensively vascularized compared with those grown with normal fibroblasts. Here, HRAS is linked to breast carcinoma.