Characteristics of IDH Mutations in Bile Duct Carcinoma in a Chinese Population

A retrospective analysis in a large Chinese patient cohort with bile duct carcinoma indicated that activating IDH1/2 mutations occurred at a lower rate compared with that previously reported in the global population.

A retrospective study characterized the incidence of IDH mutations in a large cohort of bile duct carcinomas in the Chinese population; results of this study were reported at the 2021 European Society for Medical Oncology Annual Congress.

In this study, a retrospective review was conducted to identify patients with bile duct carcinoma who had undergone molecular profiling using hybridization-based targeted next-generation sequencing of tissue and/or circulating cell-free DNA samples.

A total of 874 patients with bile duct carcinoma who had undergone molecular profiling from January 2017 to March 2021 were identified. Of these, 60 IDH mutations were identified in 59 patients, the majority of which were active-site IDH1/2 mutations (5.72%, 50 of 874). Among the 60 IDH mutations, missense variations occurred in 98.3% of the samples. Active-site IDH1 mutations were identified in 36 patients, whereas active-site IDH2 mutations were identified in 14 patients. The majority of IDH1 mutations (75.0%) were IDH1-R132C mutations, whereas the majority of IDH2 mutations were IDH2-R172W (78.6%). Among the 50 active-site IDH mutations, covariations in several other genes were identified, including TP53 (7, 14%); KRAS (7, 14%); ARID1A (7, 14%); KMT2C (3, 6%); and BAP1 (3, 6%). Correlative studies found that the cohort with activating IDH mutations had a relatively lower tumor mutational burden compared with those without IDH-activating mutations (median, 3.97 vs 2.86, respectively; P = .09).

Findings from this retrospective analysis indicate that activating IDH1/2 mutations occurred at a lower rate in Chinese patients with bile duct carcinoma compared with the rates previously reported in the cholangiocarcinoma global population.

Source: Wang J, Wang D, Yuan H, et al. The characteristics of IDH mutations in Chinese bile duct carcinoma patients. Ann Oncol. 2021;32(suppl_5):S380.