CYP2D6 and hepatocellular carcinoma: CYP2A6, CYP2B6, CYP2C9, CYP2D6, CYP2E1, and CYP3A4/5 had higher Vmax values in HCC patients, while the Vmax values of CYP1A2 and CYP2C8 were significantly reduced relative to control samples.