Arginase-1 (ARG-1) is a key enzyme of the urea cycle found in liver that catalyzes the conversion of L-arginine into
L-ornithine and urea. ARG-1 is a highly specific and sensitive marker of benign and hepatocellular carcinoma (HCC) which is now a key target for the differential diagnosis of HCC from metastatic tumors to the liver (1-3). ARG-1 is very specific and has been shown to be more sensitive than Hep Par 1 and Glypican 3 in hepatocellular carcinomas (1-2).