Molecular Profiling of Biliary Tract Cancers in African American and Caucasian Patients

PURPOSE Biliary tract cancers (BTCs) include intrahepatic cholangiocarcinoma (ICC), extrahepatic cholangiocarcinoma (ECC), and gallbladder cancers. BTCs have a number of genomic alterations, including isocitrate dehydrogenase 1 ( IDH1 ) mutations, fibroblast growth factor receptor 2 ( FGFR2 ) rearrangements, and ERBB2 amplifications. Therapies targeting these alterations have shown clinical benefit in patients with BTCs in the United States. However, molecular differences between races in BTCs are largely unknown. In particular, the genomic profiles of African American (AA) patients with BTCs have been infrequently reported. We sought to identify key genomic differences between AA and Caucasian patients with BTCs in the United States in the Foundation Medicine and American Association for Cancer Research (AACR) GENIE databases. METHODS BTC patients from AA and Caucasian patients from the Foundation Medicine and AACR GENIE databases were retrospectively reviewed. BTCs were divided into ICC, ECC, and GBCs in the Foundation Medicine database. BTCs were divided into cholangiocarcinomas and GBCs in the AACR GENIE database. RESULTS The mean age of AA patients with BTCs was lower compared with Caucasians. TP53 and FGFR2 alterations were significantly more frequent in AA patients compared with Caucasian patients with BTCs. IDH1 mutations in Caucasian patients with BTCs were double that of AA patients. CONCLUSION The results of this study suggest that significant genomic differences exist between races and warrant further investigation.