SPHK1 and malignant colon neoplasm: Importance of SphK1 in the regulation of colon carcinogenesis was also shown in mice models with SphK1 knockout that exerted lower susceptibility to colon cancer development induced by azoxymethane (AOM, colon carcinogen) in comparison with wild-type mice, whereas SphK1 overexpression in intestinal epithelial cells enhanced AOM-induced colon tumor [63].