SPHK1 and cancer: Recently, miR-124 has been found to be a potential tumor suppressor, which is epigenetically silenced in various types of cancer and regulates the biological behaviors of cancer cell by targeting several important genes, including rho-kinase 2 (ROCK2), enhancer of the zeste homologue 2 (EZH2), sphingosine kinase 1 (SPHK1) and the androgen receptor6, 7, 8, 9.