SPHK1 and cancer: In the primary human cervical epithelial cells (HCerEpC) and immortalized Ect1/E6E7 epithelial cells, the very same SKI-V treatment failed to significantly inhibit cell viability (CCK-8 OD, Figure 1K) and proliferation (tested by EdU staining assays, Figure 1L), indicating a cancer cell specific effect of the SphK inhibitor.