SPHK1 and hepatocellular carcinoma: SPHK1, generating sphingosine-1-phosphate (S1P), was also significantly upregulated in PBMCs of chronic HCV patients (4.84-fold) and persisted in HCC patients despite DAA treatment (1.59-fold in HCV-HCC no DAAs, 1.95-fold in SVR-HCC, and 1.91-fold in SVR patients).