Recently, Liu et al. reported that the biliary-specific transcription factor SOX9 determines the fate of YAP1 alone-dependent murine liver cancer; the chronic deletion of SOX9 in HC suppresses YAP1-mediated CCA-like tumor formation while promoting aggressive HCC tumor development, suggesting SOX9 as a major commitment of YAP1-mediated liver cancer lineage [14]. The gene discussed is SOX9; the disease is liver cancer.