Because in patients, IGHV unmutated (U-CLL) and mutated (M-CLL) clones typically differ in clinical aggressiveness (U-CLL > M-CLL) [40-42], we subdivided the full CLL cohort into U-CLL and M-CLL subtypes and compared the latter for differences in BCL2/MCL1 protein expression during cycling. This evidence concerns the gene MCL1 and B-cell chronic lymphocytic leukemia.