In chronic myeloid leukemia (CML) cell lines, SK/S1P mediated resistance to imatinib (12), whereas increasing ceramide levels via overexpression of ceramide synthase (an enzyme that is responsible for ceramide production) and increased imatinib-induced apoptosis (9). This evidence concerns the gene TLCD3B and chronic myelogenous leukemia, BCR-ABL1 positive.