MAX and cholangiocarcinoma: C-MYC is a basic helix-loop-helix leucine zipper transcription factor that forms a heterodimeric complex with MAX (MYC-associated factor X) and binds with the E-box sequence to activate transcription of target genes.5 We previously reported the importance of C-MYC in the murine model of CCA.5 It has been established that MAX acts as a tumor suppressor and rewires metabolism in small-cell lung cancer.16 Paradoxically, MAX deletion destabilizes MYC protein and abrogates Eμ-MYC lymphoma development.17 The role of MAX in CCA development remains largely unknown.