We have shown before[10] that significantly reduced ability of chronic B-cell leukemia (B-CLL) cells to enter spontaneous apoptosis is associated with grossly increased total amount and activity of the proteolytic enzyme, μ-calpain, member of the so-called calpain-calpastatin system (CCS) consisting of a group of proteases–calpains—and their endogenous inhibitor–calpastatin47. The gene discussed is CAST; the disease is B-cell chronic lymphocytic leukemia.