BCL2L1 and colorectal carcinoma: The lack of a spontaneous phenotype argues for a dispensability of Bcl-xL under normal conditions, which might be due to the per se high cellular turnover rates of IECs.16 Since we found Bcl-xL being strongly upregulated in human CRC, we supposed that Bcl-xLIEC-KO mice could be more resistant to experimentally induced carcinogenesis.