We have shown strong anti-apoptotic role of excessively expressed μ-calpain in human chronic and acute leukemias derived from the lymphoid (B-cell) lineage [12, 13], as well as the expression and the age-dependent changes in the amounts of CCS proteins in human peripheral blood lymphocytes [19] and, in a preliminary report, increased activity of calpains in the T lymphocytes of rheumatoid arthritis (RA) patients [15]. This evidence concerns the gene CAPN2 and acute leukemia.