THY1 and neoplasm: Thy1, a marker of myoepithelial and fibroblastic cells [64], [65], has been linked to mammary CSCs, as a small subset of Thy1+/CD24+ cells, comprising 1%–4% of the tumor cells purified from mammary carcinomas in MMTV-Wnt-1 mice, has been found to behave like CSCs [33].