PTEN and colorectal carcinoma: These conflicting data suggested that a loss of PTEN is a common mechanism of deregulating the PTEN/PI3K-AKT pathway, which plays an important role in the process of CRC tumorigenesis [30, 31] but that sometimes the deregulation of other pathways, such as inactivation of transforming growth factor-β signaling, is required to complete the process [32].