Multigene mutational profiling of cholangiocarcinomas identifies actionable molecular subgroups

Area of Science:

• Oncology
• Genetics
• Molecular Biology

Background:

• Biliary cancers, including intrahepatic cholangiocarcinoma (ICC), extrahepatic cholangiocarcinoma (ECC), and gallbladder carcinoma (GBC), are complex diseases with diverse molecular profiles.
• Understanding the genetic landscape of these tumors is crucial for developing effective targeted therapies.

Purpose of the Study:

• To comprehensively assess the mutational landscape of biliary cancers using next-generation sequencing.
• To identify specific genetic alterations and molecular subgroups within ICC, ECC, and GBC.
• To investigate the potential for targeted drug development based on identified mutations.

Main Methods:

• Multigene next-generation sequencing of 56 genes in 153 biliary cancer samples (70 ICC, 57 ECC, 26 GBC).
• Immunohistochemistry to assess the expression of EGFR and mTOR pathway genes.
• Statistical analysis, including multivariate analysis, to identify predictors of survival and characteristic mutations.

Main Results:

• At least one mutation was found in 77% of biliary cancers.
• Frequent mutations included KRAS (28%), TP53 (18%), ARID1A (12%), and IDH1/2 (9%).
• IDH1/2 and BAP1 mutations were characteristic of ICC, while KRAS and TP53 were more common in ECC and GBC. TP53 mutations and tumor stage predicted survival.
• Actionable mutations were identified in 68% of cases, including KRAS/NRAS/BRAF (34%) and alterations in the mTOR pathway (19% by mutation, 51% by IHC).

Conclusions:

• Biliary cancers exhibit significant genetic heterogeneity, with distinct molecular subgroups.
• Specific mutations like IDH1/2 and BAP1 are associated with ICC, suggesting subtype-specific therapeutic strategies.
• The high prevalence of actionable mutations supports the exploration of targeted therapies and clinical trials for biliary cancer patients.