Molecular profiling of the biphasic components of hepatic carcinosarcoma by the use of targeted next-generation sequencing.

To better understand the tumourogenesis and molecular features of hepatic carcinosarcoma (HCS). We selected 13 cases of HCS, including the clinicopathological and immunohistochemical features, and analysed the molecular alterations in separately microdissected carcinomatous and sarcomatous components in eight cases by using targeted next-generation sequencing with a panel of 329 cancer-related genes. As a result, transitional areas were observed between the two components of HCS in all cases. Concordance and overlap in genetic alterations were identified in the two histological components of the eight HCS patients, indicating the clonal relatedness of the two tumour components. The most common gene alterations found in both components were TP53 (75%, 6/8) and NF1/2 (38%, 3/8) mutations and VEGFA amplification (25%, 2/8), which may be strongly associated with HCS tumorigenesis. Unique mutations and amplifications found only in one component were also identified. Amplifications involving MET (38%, n = 3/8) and PDGFRA (25%, n = 2/8) were present only in the sarcomatous components, whereas mutation affecting ERBB4 (25%, n = 2/8) and amplifications of CCND1 and FGF3/4/19 (38%, n = 3/8) were present only in the carcinomatous components, indicating their involvement in the clonal evolution of HCS. Furthermore, multiple potential therapeutic targets were identified for HCS. Our findings indicate that HCS could have been of monoclonal origin, and that the diverse clonal evolution might be driven by special molecular alterations in each tumour component. Our results also identify multiple therapeutic targets of HCS, which are valuable for the personalised treatment of HCS.