SPHK2 and malignant colon neoplasm: Furthermore, the colon cancer epithelial cell line HCT116 was susceptible, as most cancer cells are, to growth inhibition by either SPHK1-I or SPHK2-I, but they were even more susceptible earlier on to the effects of the SPHK1-I when a mutation in D816V-KIT was additionally introduced (Figure S2B in Supplementary Material).