Prognostic Model for the Risk Stratification of Early and Late Recurrence in Hepatitis B Virus-Related Small Hepatocellular Carcinoma Patients with Global Histone Modifications

BACKGROUND AND AIM: To assess the profile of global histone modifications in small hepatocellular carcinoma (small HCC) and identify its prognostic value in predicting recurrence. METHODS: The expression profiles of global histone modifications, including H2AK5AC, H2BK20AC, H3K4me2, H3K9AC, H3K18AC, H4K12AC, and H4R3me2, were evaluated with immunohistochemistry in 335 HBV related small HCC patients. Two histone signature classifiers were then developed using least absolute shrinkage and selection operator Cox regression. A nomogram was built using the classifier and independent risk factors. The performances of the classifier and nomogram were assessed by receiver operating characteristic curves. RESULTS: Histone modifications were more pronounced in tumor tissues than in adjacent liver tissues. In tumor tissues, the risk score built based on the seven-histone signature exhibited satisfactory prediction efficiency, with an AUC = 0.71 (0.63–0.79) for 2-year survival in the training cohort. Patients with a high risk score had shorter recurrence-free survival than those with a low risk score (HR: 1.96, 95% CI: 1.24–3.08, p = 0.004; HR: 1.95, 95% CI: 1.12–3.42, p = 0.019; and HR: 1.97, 95% CI: 1.39–2.80, p < 0.001 for the training, validation and total cohorts, respectively). Furthermore, the statistical nomogram built using the histone classifier for early recurrence had a C-index = 0.68. In non-neoplastic liver tissues, the hepatic signature based on H3K4me2 and H4R3me2 was related to late recurrence (HR: 2.00, 95% CI: 1.15–3.48, p = 0.01). CONCLUSION: Global histone modifications in tumor and adjacent liver tissues are novel predictors of early and late recurrence, respectively, in HBV-related small HCC patients.