Chromosome 8q24 amplification predicts prognosis for patients with advanced hepatocellular carcinoma (HCC).
e15654 Background: China accounts for over 50% of global liver cancer burden and most patients have advanced disease at the time of diagnosis. Currently, very little is known about the mutational landscape of Chinese HCC patients because it is risky to perform tissue biopsy on late-stage patients. In this study, this problem was overcome by genetic profiling using circulating tumor DNA (ctDNA) and frequently mutated loci were evaluated as biomarkers for prognosis prediction. Methods: Targeted next generation sequencing (NGS) was performed on ctDNA obtained from patients with advanced HCC using a 150-gene panel. The relationship between overall survival (OS) and genetic alterations was analyzed using Kaplan-Meier method. The predictive value of frequently mutated genes was then validated using 607 western HCC cases of the cBioPortal (http://www.cbioportal.org,including TCGA and other two studies). Impact of 8q24 amplification on transcription of other genes was analyzed using mRNA data from TCGA database. Results: Fifty-eight Chinese advanced HCC patients were enrolled and ctDNA was detected in 89.7% of them. The most frequently mutated genes were TP53 (57.7%) and TERT (30.8%) and amplification of chromosome 8q24 occurred at a higher frequency (20.0%) than previously reported for western HCC patients. The 8q24 amplified patients showed significantly shorter OS compared to those without 8q24 amplification (4.9 months vs. Not Reached, p = 0.008). This was confirmed by the cBioPortal database, where 8q24 amplification, which was identified in 10.1% of the HCC cases, was also associated with decreased OS (55.6 months vs.102.7 months, p < 0.001). Gene expression analysis using TCGA mRNA data revealed that upon 8q24 amplification, transcription of 56 genes was upregulated and 169 genes were downregulated, among which ABC transporters, RAS signaling and Hippo signaling pathways were significantly enriched in 8q24 amplified population (p = 0.001, 0.015, 0.027, respectively) as suggested by KEGG analysis. Conclusions: Amplification of chromosome 8q24 ocurred at a higher frequency in Chinese HCC patients and showed promise as a biomarker for prognosis prediction.