Finally, the abundance of IDH1/2 mutations in gliomas and cholangiocarcinomas, but lack of TET2 mutations, are likely a reflection of TET enzymes functioning in tissue specific patterns—TET1, for example, has very recently been shown to be an oncogenic driver in IDH‐wt cholangiocarcinoma.135. This evidence concerns the gene IDH1 and cholangiocarcinoma.