BAK1 and rectal neoplasm: We observed high baseline death in mucinous cells in-vitro and high cleaved-Caspase 3 levels in resected rectal tumors, suggesting that Bcl-xL was unable to prevent the activation of pro-apoptotic Bak and Bax under baseline conditions, for example when cancerous cells are subjected to ‘physiological’ mitogenic, metabolic or environmental stress.