SPHK1 and cancer: SphK1 has been found to be overexpressed in many types of human cancers including prostate cancer, gastric cancer, breast cancer, lung cancer, glioma, Hodgkin's lymphoma, and head and neck SCC.3–5 It is involved in tumor progression, invasion, metastasis, and radiation and chemoresistance.3–5 In head and neck SCC, elevated SphK1 levels are associated with poor outcomes and a reduction in SphK1 levels is associated with increased patient survival.3 Therefore, SphK1 is believed to be a promising target for cancer and inflammatory diseases.