As a diagnostic tool Iizuka et al. evaluated the use of a real-time PCR assay for levels of the glutathione S-transferase pi (GSTP1) gene in cfDNA in the blood of 52 patients with HCC associated with HCV, 30 HCV carriers without known HCC, and 16 HCV-negative non-cancer patients. The gene discussed is GSTP1; the disease is hepatocellular carcinoma.