ARG1 and hepatocellular carcinoma: Histological evaluation confirmed an HCC tumor showing architectural distortion characterized by expansion of liver cords, nuclear pleomorphism, anisonucleosis, and nodular fibrosis in a background of dense collagen bands within adjacent non-tumorous liver consistent with METAVIR grade 2–3 fibrosis (Figure 5D), as well as arginase-1 and KRASG12D positivity (Figure 5E).