This increased sensitivity may be due to the lower basal S1P/C16 Cer ratio displayed in the pA cells relative to the other cancer groups (Figure 7); a less extreme level of basal pro-proliferative S1P relative to C16 Cer may have made it so a lower concentration of SK1 inhibitor was sufficient to restore the healthy “hTert-like” balance in the sphingolipid rheostat in pA cells compared to the other cancer groups whose S1P/C16 Cer ratios were significantly higher (P < 0.05) (Figure 7). Here, SPHK1 is linked to cancer.