Metabolic liver cancer: associations of rare and common germline variants in one-carbon metabolism and DNA methylation genes.

Animal studies implicate one-carbon metabolism and DNA methylation genes in hepatocellular carcinoma (HCC) development in the setting of metabolic perturbations. Using human samples, we investigated the associations between common and rare variants in these closely related biochemical pathways and risk for metabolic HCC development in a multicenter international study. We performed targeted exome sequencing of 64 genes among 556 metabolic HCC cases and 643 cancer-free controls with metabolic conditions. Multivariable logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for multiple comparisons. Gene-burden tests were used for rare variant associations. Analyses were performed in the overall sample and among non-Hispanic whites. The results show that among non-Hispanic whites, presence of rare functional variants in ABCC2 was associated with 7-fold higher risk of metabolic HCC (OR = 6.92, 95% CI: 2.38-20.15, P = 0.0004), and this association remained significant when analyses were restricted to functional rare variants observed in ≥2 participants (cases 3.2% versus controls 0.0%, P = 1.02 × 10-5). In the overall multiethnic sample, presence of rare functional variants in ABCC2 was nominally associated with metabolic HCC (OR = 3.60, 95% CI: 1.52-8.58, P = 0.004), with similar nominal association when analyses were restricted to functional rare variants observed in ≥2 participants (cases 2.9% versus controls 0.2%, P = 0.006). A common variant in PNPLA3 (rs738409[G]) was associated with higher HCC risk in the overall sample (P = 6.36 × 10-6) and in non-Hispanic whites (P = 0.0002). Our findings indicate that rare functional variants in ABCC2 are associated with susceptibility to metabolic HCC in non-Hispanic whites. PNPLA3-rs738409 is also associated with metabolic HCC risk.

Derivation and validation of the nonalcoholic fatty liver disease cirrhosis score (NCS) to distinguish bridging fibrosis from cirrhosis.

Separation of bridging fibrosis from cirrhosis in non-alcoholic fatty liver disease (NAFLD) is critical to guide management. Therefore, it was the aim of this study to develop an easy-to-perform score distinguishing F3 and F4 fibrosis in NAFLD. A derivation cohort comprising 251 NAFLD patients with F3 or F4 was used to develop the NAFLD Cirrhosis Score (NCS). The NCS was validated in three independent cohorts with liver histology comprising 1666 participants from the STELLAR trials, 47 patients from China and 2058 patients from the European NAFLD Registry. A model including INR, gGT, ALT, platelets and age discriminated best between patients with bridging fibrosis and cirrhosis with an area under the curve (AUC) of 0.733 (95%CI 0.671-0.795). The diagnostic performance of the NCS was similar in the STELLAR studies (AUC 0.700; 95%CI 0.680-0.730) and a smaller cohort from China (AUC 0.727; 95%CI 0.533-0.921). In the European NAFLD Registry, spanning all histological fibrosis stages, the NCS exhibited an AUC of 0.798 (95%CI 0.766-0.830) to detect cirrhosis. We derived two NCS cut-off values (<64.5 and >79.17) to classify patients at low, intermediate, or high risk for the presence of cirrhosis. Using these cut-offs, further diagnostic workup could be avoided by ruling in or ruling out cirrhosis in approximately half of the patients. Furthermore, NCS identified patients at risk for progression to cirrhosis in the F3 cohort and liver-related outcomes in the F4 cohort. CONCLUSION: The NCS is a simple tool to improve the identification of compensated cirrhosis within the large group of advanced disease stage and provides prognostic information. Overall, the differentiation of F3 from F4 disease using standard laboratory remains difficult and does not exceed moderate accuracy.