PIK3CA and cholangiocarcinoma: Furthermore, AKR1C1–CYP1B1–cAMP signaling axis, AMDHD1/TGF-β signaling pathway, EZH2-mediated WNT7B/β-catenin pathway, VEGF/FGF signaling, MUC3-MAPK/ERK pathway, EGFR/SREBP-1 pathway, and lipopolysaccharide-mediated METTL3/PI3K/AKT signaling have been identified in CCA development [115–120].