IDH1 and cholangiocarcinoma: Therefore, ETS‐related transcription factor—ELF3—may act as an inhibitor of CCA,43 consistent with the findings of Nakamura et al In previous studies, targeted sequencing was performed on select cancer‐related genes including IDH1/2, FGFR2 and CDKN2A; the most significant changes were reported in ARID1A, IDH1/2 and TP53 (each of which was found in 36% of the tumours) and MCL1 (amplified in 21% of the tumours).38, 40