Based on the functional enrichment analysis, DEGs in early- versus late-onset ICC samples also were closely associated with oxidative phosphorylation and ROS pathways, which act as regulators of important signaling pathways in carcinogenesis and cancer progression.27,28 Of note, the SNP mutational analysis demonstrated that KRAS was mutated in 10% of ICC samples, of which none was early-onset ICC. This evidence concerns the gene KRAS and intrahepatic cholangiocarcinoma.