BCL2L1 and neoplasm: As a proof of evidence for therapeutic strategies, caspase 3 activation and Bcl-xL depletion are correlated with a decreased number of CTCs and metastasis (119).The interactions of certain Bcl-2 proteins occur at the BH3 domains (178), and BH3 profiling measures the relative interactions of pro- and anti-apoptotic proteins to determine whether a tumor cell is near the threshold to activate apoptosis through mitochondrial outer membrane permeabilization (178, 179).