BCL2 and colorectal carcinoma: In-line with the above mentioned findings, human CRC cell lines were found to be highly sensitive towards selective inhibition of BCL-XL but not MCL-1 or BCL-2, even though binding affinity of WEHI-539 is with a dissociation constant (KD) of 0.6 nM lower than that of S63845 (KD = 0.19 nM)47,48.