CD44 and cancer: The selected surface markers have been previously identified as stem cell markers in the kidney (i.e. CD24, CD29, CD133)15, cancer stem cell markers in other malignancies (CD24, CD29, Epcam, CD44, MET, CD90, ALDH1A1 activity)16–21, and in the kidney (CD133, CD24, CD105, CXCR4)8,9,15,22.