CERK and neoplasm: Enhanced S1P and C1P-producing enzymes (CERK, SphK, and ATX) and activation of S1PRs in tumor tissues are closely related to poor prognostic factors that result in tumor metastasis and recurrence while attenuating chemo- and antitumor therapies, deteriorating the survival of tumor patients36–39 (Fig. 2 and Table 1).