There are dozens of papers proving their antitumour efficacy in vitro and in vivo (reviewed in Alshaker et al., 2013) and two molecules are already in clinical trials: SK1 inhibitor phenoxodiol (Veyonda) for prostate cancer, non-small cell lung cancer and sarcoma; and SK2 inhibitor ABC294640 (opaganib) for advanced solid tumors and multiple myeloma. This evidence concerns the gene SPHK2 and Familial prostate cancer.