Comprehensive molecular profiling of intra- and extrahepatic cholangiocarcinomas: potential targets for intervention

Purpose: Various genetic driver aberrations have been identified among distinct anatomic and clinical subtypes of intrahepatic and extrahepatic cholangiocarcinoma, and these molecular alterations may be prognostic biomarkers and/or predictive of drug response. Experimental Design: Tumor samples from patients with cholangiocarcinoma who consented prospectively were analyzed using the MSK-IMPACT platform, a targeted next generation sequencing assay that analyzes all exons and selected introns of 410 cancer-associated genes. Fisher's exact tests were performed to identify associations between clinical characteristics and genetic alterations.

Results: 195 patients were studied: 78% intrahepatic and 22% extrahepatic cholangiocarcinoma. The most commonly altered genes in intrahepatic cholangiocarcinoma (IHC) were IDH1(30%), ARID1A(23%) BAP1(20%), TP53(20%) and FGFR2gene fusions (14%). A tendency towards mutual exclusivity was seen between multiple genes in IHC including TP53:IDH1, IDH1:KRAS, TP53:BAP1, IDH1:FGFR2. Alterations in CDKN2A/B and ERBB2 were associated with reduced survival and time to progression on chemotherapy in patients with locally advanced or metastatic disease. Genetic alterations with potential therapeutic implications were identified in 47% of patients, leading to biomarker directed therapy or clinical trial enrollment in 16% of patients. Conclusions: Cholangiocarcinoma is a genetically diverse cancer. Alterations in CDKN2A/Band ERBB2are associated with negative prognostic implications in patients with advanced disease. Somatic alterations with therapeutic implications were identified in almost half of patients. These prospective data provide a contemporary benchmark for guiding the development of targeted therapies in molecularly profiled cholangiocarcinoma, and support to the use of molecular profiling to guide therapy selection in patients with advanced biliary cancers.

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