Replacement of Fhit in most Fhit-deficient cancer cells suppresses tumorigenicity (Siprashvili et al, 1997; Ishii et al, 2001; Sevignani et al, 2003) and FHIT-viral gene therapy, using adeno or AAV viral vectors, prevents and reverses carcinogen-induced gastric cancers in Fhit-deficient mice (Dumon et al, 2001; Ishii et al, 2003). The gene discussed is FHIT; the disease is gastric cancer.