Arginase-1 (Arg-1) is a binuclear manganese metalloenzyme that catalyzes the hydrolysis of arginine to ornithine and urea.
Arginase catalyzes the hydrolysis of arginine to ornithine and urea. At least two isoforms of mammalian arginase exist (types I - ARG1 and II - ARG2) which differ in their tissue distribution, subcellular localization, immunologic crossreactivity and physiologic function.
The type I isoform ARG1 encoded by this gene, is a cytosolic enzyme and expressed predominantly in the liver as a component of the urea cycle.
Pathology
Inherited deficiency of this enzyme results in argininemia, an autosomal recessive disorder characterized by hyperammonemia.
The distinction of hepatocellular carcinoma (HCC) from metastatic tumor in the liver often presents a diagnostic challenge that carries significant impact on prognostication and therapy.
The number of diagnostically useful immunohistochemical markers of hepatocytes is limited to hepatocyte paraffin antigen (HepPar-1), polyclonal carcinoembryonic antigen, and CD10, with alpha-fetoprotein and glypican-3 labeling HCCs.
Immunochemistry
Arg-1 represents a sensitive and specific marker of benign and malignant hepatocytes that may ultimately prove to be a useful diagnostic tool in routine surgical pathology practice.
References
Arginase-1: a new immunohistochemical marker of hepatocytes and hepatocellular neoplasms. Yan BC, Gong C, Song J, Krausz T, Tretiakova M, Hyjek E, Al-Ahmadie H, Alves V, Xiao SY, Anders RA, Hart JA. Am J Surg Pathol. 2010 Aug;34(8):1147-54. PMID: 20661013
