Although no alteration of MHC II was detected in plasma membranes of antigen-presenting cells (APC) from non-exposed caspase-2-deficient mice, an upregulation could be seen in protein lysates from caspase-2−/− B-cells, as well as in lysates from acute monocytic leukemia (AMoL) and acute myeloid leukemia (AML) cell lines, when caspase-2 was stably suppressed by RNAi. This evidence concerns the gene CASP2 and acute monocytic leukemia.