CAFs may also be derived from bone marrow-derived mesenchymal stem cells (BM-MSCs), as PDGFR-α−, CD45−, CD34− BM-MSCs are recruited into primary breast tumors to differentiate into α-SMA+, PDGFR-α−, CD45−, CD34− CAFs (57). Here, PDGFRA is linked to breast neoplasm.