PRKCD and malignant colon neoplasm: Coward et al. [6] treated colon cancer cells with 12 μM safingol and found that safingol inhibited PKCβ1, PKCδ, and PKCε, and also inhibited the phosphorylation of the PI3k/Akt/mTOR pathway and mitogen-activated protein kinase (MAPK) pathway.