Based on our previous characterization of the p33 form in cancer cells from hematopoietic origin, i.e., acute myeloid leukemia (36), we tested the distribution of APE1 in EXE of OCI-AML3 (expressing the mutated NPM1c+ protein) and OCI-AML2 control cells (45). This evidence concerns the gene APEX1 and acute myeloid leukemia.