However, other markers were overexpressed on CSCs of a subset of tumor types such as CD117 (c-kit) in glioblastoma, ovarian and lung cancers [18,19,20]; CD24 (Heat-Stable Antigen) in pancreatic cancer [21]; CXCR4 (chemokine receptor) in pancreatic and breast cancers [21,22]; CD90 (thymocyte differentiation) in breast and colon cancers [22,23], CD49f (Integrin α6) in prostate cancer [24,25] (Table 1). This evidence concerns the gene KIT and breast cancer.