The non-specific inhibitor of SKs dimethylsphingosine (DMS) has been shown to inhibit leukaemia, colon, epidermoid, and lung tumour cell growth and to reduce metastasis in vivo [155,156], as well as increase the sensitivity of human leukaemia cells to apoptosis in response to radiation, TNF-α and Fas ligands [157]. The gene discussed is TNF; the disease is leukemia.