The expression of acid ceramidase, a lysosomal enzyme in the sphingolipid pathway that hydrolyses the pro-apoptotic sphingolipid ceramide to sphingosine, is elevated in several malignancies and has been identified as a therapeutic target in glioblastoma and in melanoma, where ablation of its activity interferes with cancer-initiating cells (16, 17). This evidence concerns the gene ASAH1 and cancer.