A meta-analysis combining several studies determining the in vitro expression or activity of six hepatic CYP enzymes (CYP1A2, 2C8, 2C9, 2C19, 2E1 and 3A4) led to inconclusive results for the CYP enzyme expression/activity in cancer subjects relative to healthy volunteers ([20]; references within). The gene discussed is CYP1A2; the disease is cancer.