The mRNA levels of SphK1 were significantly increased in breast, colon, lung, ovary, uterus, and kidney cancer patients, as well as in acute leukemia patients [12,13,14], and the downregulation of SphK1 decreased the epidermal growth factor and reduced prolactin- and E2-induced migration in metastatic breast cancer [7]. Here, SPHK1 is linked to kidney cancer.