Clinical utility of post-ablation liver tumor biopsy and possibility of gene mutation analysis

Radiofrequency ablation (RFA) is regarded as a first-line treatment for hepatocellular carcinoma (HCC) at an early stage. When treated with RFA, tumor biopsy may not be performed due to the risk of neoplastic seeding. We previously revealed that the risk of neoplastic seeding is significantly reduced by performing biopsies after radiofrequency ablation (RFA). In this study, we investigated the possibility of pathological evaluation and gene mutation analysis of post-RFA tumor specimens. RFA was performed on diethylnitrosamine-induced mouse liver tumor, and tumor samples with or without RFA were subjected to whole exome sequencing. Post-RFA human liver tumor specimens were used for detection of TERT promoter mutations and pathological assessment. The average somatic mutation rate, sites of mutation, and small indels and base transition patterns were comparable between the non-treated and post-RFA tumors. We identified 684 sites of non-synonymous somatic substitutions in the non-treated tumor and 704 sites of non-synonymous somatic substitutions in the post-RFA tumor, with approximately 85% in common. In the human post-RFA samples, the TERT promoter mutations were successfully detected in 40% of the cases. Pathological evaluation was possible with post-RFA specimens, and in one case, the diagnosis of adenocarcinoma was made. Our findings suggest that post-RFA liver tumor biopsy is a useful and safe method for obtaining tumor samples that can be used for gene mutation analysis and for pathological assessment. This article is protected by copyright. All rights reserved.