In a recent work, we analyzed the transcriptomic and mutational profiles of paired primary and recurrent ICCs—we found that 5 out of 15 patients (33%) harbored an IDH1 R132x mutation; of them, 4 displayed a naïve mutation only in the recurrent counterpart, suggesting that IDH1m could be a marker of progression in ICC [15]. The gene discussed is IDH1; the disease is intrahepatic cholangiocarcinoma.