Discussion
From a cohort of 28.868 patients with different types of solid tumors, a high frequency of IDH1/IDH2 mutations were observed not only in biliary tract cancer, but also liver cancer, lung cancer, colorectal cancer and others. The reprogramming of cellular metabolism is a fundamental characteristic of cancer, and IDH1/2 mutations represent key therapeutic targets in this arena. Somatic IDH1/2mutations are found in multiple solid tumors, and mounting evidence indicates that they contribute to premalignant disorders as well as early and late cancers. And then, another interesting point, we found that TMB was higher in other gastrointestinal tumors. However, in biliary tract cancer, IDH mutation accompanied by low TMB indicates that IDH would be a driver gene in biliary tract cancer. With the continuous emergence of IDH inhibitors, a considerable number of patients with solid tumors carrying IDH1/2 gene mutations may be more likely to benefit from IDH inhibitors, which is worth further expectation and exploration in clinical studies.