ASAH2 and intestinal cancer: Although mice have no obvious phenotypic defects when the neutral ceramidase is mutated, they have defects in lipid metabolism in the intestine and increased susceptibility to intestinal cancer (Schmelz et al., 2001; Symolon et al., 2004), indicating that the neutral ceramidase affects ceramide and sphingosine levels in the gastrointestinal tract by regulating dietary sphingolipid metabolism (Kono et al., 2006).