CD44 and breast carcinoma: Since then, CSCs have been reported in other cancers: breast cancer (CSC markers: CD44, CD24, and ALDH-1) [3,4], colon cancer (CSC markers: CD24, CD44, CD133, and LGR5) [5,6,7], and melanoma (CSC markers: CD34 and ABCB5) [8,9].