Transcriptomic and histopathological analysis of cholangiolocellular differentiation trait in intrahepatic cholangiocarcinoma

Background & Aims Intrahepatic cholangiocarcinoma (iCCA) is a heterogeneous entity with diverse etiologies, morphologies, and clinical outcomes. Recently, histopathological distinction of cholangiolocellular differentiation (CD) of iCCA has been suggested. However, its genome-wide molecular features and clinical significance remain unclear. Methods Based on CD status, we stratified iCCAs into iCCA with CD (n=20) and iCCA without CD (n=102), and performed an integrative analysis using transcriptomic and clinicopathological profiles. Results iCCA with CD revealed less aggressive histopathological features compared to iCCA without CD, and iCCA with CD showed favorable clinical outcomes of overall survival and time to recurrence than iCCA without CD (P < 0.05 for all). Transcriptomic profiling revealed that iCCA with CD resembled an inflammation-related subtype, while iCCA without CD resembled a proliferation subtype. In addition, we identified a CD signature that can predict prognostic outcomes of iCCA (CD_UP, n=486 and CD_DOWN, n=308). iCCAs were subgrouped into G1 (positivity for CRP and CDH2, 7%), G3 (positivity for S100P and TFF1, 32%), and G2 (the others, 61%). Prognostic outcomes for OS (P=0.001) and TTR (P=0.017) were the most favorable in G1-iCCAs, intermediate in G2-iCCAs, and the worst in G3-iCCAs. Similar result was confirmed in the iCCA set from GSE26566 (n=68). Conclusions CD signature was identified to predict the prognosis of iCCA. The combined evaluation of histology of CD and protein expression status of CRP, CDH2, TFF1, and S100P might help subtyping and predicting clinical outcomes of iCCA. This article is protected by copyright. All rights reserved.