Age and Sex Affects the Frequency and Mutation Type of <i>FGFR2</i> Alterations in Cholangiocarcinoma

PURPOSE FGFR2 alterations are infrequent but currently represent the most common targetable mutation in cholangiocarcinoma. We performed a large-scale genomic analysis to assess associations between FGFR2 and other driver gene alterations in cholangiocarcinoma with patient demographics. METHODS Clinical and molecular data for patients with intrahepatic cholangiocarcinoma were abstracted from the Foundation Medicine (FMI) and Genomics, Evidence, Neoplasia, Information, Exchange (GENIE) genomic databases. The Chi-squared test was used to assess the association between sex and alterations in driver genes. FGFR2 fusion partners were analyzed using descriptive statistics. RESULTS Across both FMI (N = 7,859) and GENIE (N = 1,395) cohorts, FGFR2 rearrangements were more frequent in female than male patients with cholangiocarcinoma (odds ratio, 1.69 and 2.45). By contrast, FGFR2 missense mutations, TP53 mutations, and KRAS mutations were not associated with sex. Stratifying patients by age groups showed that FGFR2 rearrangements were specifically enriched in younger ages (&lt;45 years). Although the most common FGFR2 fusion partners were shared across both sexes, a subset of fusion partners was recurrent and uniquely associated with female or male patients. CONCLUSION FGFR2 rearrangements but not other driver alterations in cholangiocarcinoma are concentrated in young female patients, where the prevalence reached nearly 20% across two large patient cohorts. These results suggest that the molecular basis of FGFR2 rearrangements may be distinct between sexes. These results indicate the importance of genetic testing in cholangiocarcinoma, particularly for younger patients, and suggest that patient recruitment strategies in trials for FGFR2-targeting therapies should seek to reduce barriers to enhance the enrollment of young female patients.