PRKD1 and malignant colon neoplasm: Additional clues to the mechanisms by which PKD regulates SphK2 activity and cellular transport in colon cancer cells in response to treatment with NaBT were provided by the study showing that NaBT elicited early ERK1/2 activation, and down-regulation of ERK1/2 activity in HCT116 colon cancer cells by specific UO126 inhibitor reduced SphK2 activity and its translocation from the nucleus [106].