PROM1 and malignant colon neoplasm: Because Akt and its downstream target mTOR were activated in serum‐starved CD133‐expressing colon cancer cells, it is possible that the CD133‐Akt‐mTOR regulatory axis positively regulates CD133 production through augmentation of protein synthesis‐related p70‐S6K and 4E‐BP1 [37].