BCL2 and B-cell chronic lymphocytic leukemia: Recently, whole-exome sequencing of biopsy samples from seven patients with multiply relapsed MCL who received venetoclax-based therapies has revealed that unlike in CLL, BCL2 mutations are infrequent in venetoclax-resistant MCL, occurring in only one patient at progression; instead, the acquisition of non-BCL2 mutations, including alterations in TP53, SMARC4, CELSR3, CCND1 and KMT2D, may play a role in disease progression [113].