Somatic Mutation Profiling of Intrahepatic Cholangiocarcinoma: Comparison between Primary and Metastasis Tumor Tissues.

INTRODUCTION

Intrahepatic cholangiocarcinoma (ICC) exhibited increasing incidence and mortality around the world, with a 35% five-year survival rate. In this study, the genetic alteration of primary ICC and metastasis ICC was exhibited to discover novel personalized treatment strategies to improve the clinical prognosis.

METHODS

Based on 153 primary and 49 metastasis formalin-fixed paraffin-embedded ICC samples, comprehensive genomic profiling was carried out.

RESULTS

In primary tumor samples (PSs) and metastasis tumor samples (MSs), the top alteration genes were TP53 (41.8% vs 36.7%), KRAS (30.7% vs 36.7%), and ARID1A (22.2% vs 14.2%). In the top 20 most frequent alteration genes, BRAF showed lower mutation frequency in MSs as compared to PSs (0 vs 11.1%, =0.015), while LRP1B exhibited opposed trend (22.4% vs 10.4%, =0.032). In PSs, patients with MSI-H showed all PDL1 negative, and patients with PDL1 positive exhibited MSS both in PSs and MSs. It was found that the Notch pathway had more alteration genes in MSI-H patients (=0.027). Furthermore, the patients with mutated immune genes in PSs were more than that in MSs (28.8% vs 8.2%, =0.003, odd ratio = 0.2). Interestingly, the platinum drug resistance pathway was only enriched by mutated genes of MSs.

CONCLUSIONS

In this study, the identification of two meaningful mutated genes, BRAF and LRP1B, highly mutated immune gene harbored by primary ICC patients. Both in PSs and MSs, no patients with MSI-H showed PDL1 positive. The Notch pathway had more alteration genes in patients with MSI-H. And the enrichment of the platinum drug resistance pathway in MSs might offer reference for the novel therapeutic strategy of ICC.