Liquid Biopsy Test Based on a Sensitive DNA Methylation Assay for Diagnosing Early-Stage Hepatocellular Carcinoma: Which Is Better as a Combination Marker of AFP and PIVKA-II, Methylated SEPT9 or HOXA1?

Although a combination test of alpha-fetoprotein（AFP）and protein induced by vitamin K absence or antagonist-II（PIVKA-II）is covered by public insurance in Japan for the screening of hepatocellular carcinoma（HCC）in patients with chronic hepatitis and/or cirrhosis, its diagnostic performance for early-stage HCC is limited. To resolve this, we investigated whether a liquid biopsy of methylated SEPT9 and methylated HOXA1 may complement the diagnostic performance of AFP and PIVKA-II for early-stage HCC. We measured AFP, PIVKA-II, and copy numbers of methylated SEPT9 and HOXA1 in serum from 25 healthy controls, 30 patients with chronic liver disease, and 78 patients with HCC（including 44 patients with early-stage HCC）．Sensitivity and specificity for early-stage HCC were, respectively, 56.8% and 94.5% for the combination of AFP and PIVKA-II；77.3% and 89.1% for the combination of AFP, PIVKA-II, and methylated SEPT9；and 63.6% and 90.9% for the combination of AFP, PIVKA-II, and methylated HOXA1. Having the highest sensitivity and considerable specificity, the combination of AFP, PIVKA-II, and methylated SEPT9 appeared to be the best companion test for detecting early-stage HCC.