Molecular characterization of hepatocellular carcinoma in patients with non-alcoholic steatohepatitis.

Abstract Background and Aims Non-alcoholic steatohepatitis (NASH)-related hepatocellular carcinoma (HCC) is increasing globally, but its molecular features are not well defined. We aimed to identify unique molecular traits characterizing NASH-HCC compared to other HCC aetiologies. Methods We collected 80 NASH-HCC and 125 NASH samples from 5 institutions. Expression array (n=53 NASH-HCC; n=74 NASH) and whole exome sequencing (n=52 NASH-HCC) data were compared to HCCs of other aetiologies (n=184). Three NASH-HCC mouse models were analysed with RNAseq/expression-array (n=20). Activin A Receptor Type 2 A (ACVR2A) was silenced in HCC cells and proliferation assessed by colorimetric and colony formation assays. Results Mutational profiling of NASH-HCC tumours revealed TERT-promoter (56%), CTNNB1 (28%), TP53 (18%) and ACVR2A (10%) as the most-frequently mutated genes. ACVR2A mutation rates were higher in NASH-HCC than in other HCC aetiologies (10% versus 3%, p Conclusions NASH-HCCs display unique molecular features including higher rates of ACVR2A mutations and the presence of a newly identified mutational signature. Lay Summary Hepatocellular carcinoma (HCC) associated with non-alcoholic steatohepatitis (NASH) is increasing globally, but its molecular traits are not well characterized. Our molecular characterization has uncovered higher rates of ACVR2A mutations (10%) –a potential tumour suppressor– and the presence of a novel mutational signature (MutSig-NASH-HCC), as well as a more prominent role of a Wnt/TGF-β proliferation subclass in tumours (42%) and immunosuppressive traits in the adjacent non-tumoral tissue.