ARG1 and neoplasm: The published arginase-1 positivity rates are also markedly variable in tumor entities that are often seen in the liver such as cholangiocarcinoma (positivity described in 0–68% of cases, [8,19,24,25,26,31], breast cancer NST (0–47%), [8,18,26,29]), colorectal adenocarcinoma (0–100%) [8,26,32,33] and even hepatocellular carcinoma 45–100%, [6,8,9,11,12,22,26].