Probable mechanisms by which ASCs might increase the metastatic capacity of breast cancer cells include initiation of EMT, matrix degradation through elevated expression of MMPs, induction of angiogenesis, and secretion of paracrine factors favoring metastatic spread [51], PDGF-D [53], IL-6 [58], and IL-8 [52]. This evidence concerns the gene CXCL8 and breast cancer.