Recombinant Rabbit monoclonal / IgG 1:100 – 1:200 Research Use Only Nuclear and cytoplasmic. Human MSVA-511R Arginase 1; ARG1; liver-type arginase; type I arginase Liver:A strong staining should be seen in hepatocytes. Spleen: A moderate t strong positivity should be seen in granulocytes. Colon: Epithelial cells, smooth muscle and the vast majority of stroma cells should stain negative (few granulocytes may stain positive). Arginase 1 is expressed in hepatocytes. Arginase-1 is coded by the ARG1 gene located at 6q23. It acts as an enzyme that catalyzes the conversion of arginine to ornithine and urea in the final step of the urea cycle. Inherited deficiency of both alleles of this enzyme results in argininemia, an autosomal recessive disorder characterized by hyperammonemia and resulting in progressive neurological disorder. [1] [1] Lennartz et al. “Large-Scale Tissue Microarray Evaluation Corroborates High Specificity of High-Level Arginase-1 Immunostaining for Hepatocellular Carcinoma. Diagnostics” (Basel). 2021 Dec 14;11(12):2351. doi: 10.3390/diagnostics11122351. PMID: 34943588; PMCID: PMC8699869. Arginase-1 staining pattern in Normal Tissues with antibody MSVA-511R (images are shown in our “Normal Tissue Gallery”) Brain Cerebrum Negative. Cerebellum Negative. Endocrine Tissues Thyroid Negative. Parathyroid Negative. Adrenal gland Negative. Pituitary gland Negative. Respiratory system Respiratory epithelium Negative. Lung Negative. Gastrointestinal Tract Salivary glands Negative. Esophagus Negative. Stomach Negative. Colon Negative. Duodenum Negative. Rectum Negative. Small intestine Negative. Liver The strongest nuclear and cytoplasmic Arginase-1 staining occurs in hepatocytes. Gallbladder Negative. Pancreas Negative. Genitourinary Kidney Negative. Urothelium Negative. Male genital Prostate Negative. Seminal vesicles Negative. Testis Negative. Epididymis Negative. Female genital Breast Negative. Uterus, myometrium Negative. Uterus, ectocervix Negative. Uterus endocervix Negative. Uterus, endometrium Negative. Fallopian Tube Negative. Ovary Negative. Placenta early Negative. Pla... Arginase-1 is expressed in the vast majority of hepatocellular carcinomas but occurs only exceptionally in other tumors. A focal arginase positivity can occasionally be seen in specific cell layers of squamous cell carcinomas reflecting the granulosa cell layer of normal skin. Arginase-1 expression has been reported to occur in hepatoid carcinoma of the pancreas. The TCGA findings on Arginase-1 RNA expression in different tumor categories have been summarized in the Human Protein Atlas. Intestinal type gastric adenocarcinoma (arginase-1 negative) containing many arginase-1 positive granulocytes. Keratinizing squamous cell carcinoma of the vulva showing a weak to moderate arginase-1 immunostaining in a specific cell layer reflecting the „granular layer“ of normal skin. Hepatocellular carcinoma showing strong arginase-1 immunostaining in all tumor cells. Cancer tissue gallery Arginase-1 (MSVA-511R) publication summary Relevant publication: Lennartz et al. “Large-Scale Tissue Microarray Evaluation Corroborates High Specificity of High-Level Arginase-1 Immunostaining for Hepatocellular Carcinoma. Diagnostics” . Published in (Basel). 2021 Dec 14;11(12) A total of 14912 tumors were analyzed from 117 different tumor categories by using the following protocol: Heat-induced antigen retrieval for 5 minutes in an autoclave at 121°C in pH7,8 Target Retrieval Solution buffer. MSVA-511R at a dilution of 1:150 at 37°C for 60 minutes. Visualization of bound antibody by the EnVision Kit (Dako, Agilent). This protocol was also used for all stainings depicted in our tumor and normal tissue galleries. A nuclear and cytoplasmic arginase-1 immunostaining was predominantly observed in hepatocellular carcinoma, where 96% of 49 cancers were at least moderately positive. Although 22 additional tumor categories showed occasional arginase immunostaining, strong staining was exceedi... IHC users have different preferences on how the stains should look like. Some prefer high staining intensity of the target stain and even accept some background. Others favor absolute specificity and lighter target stains. Factors that invariably lead to more intense staining include higher concentration of the antibody and visualization tools, longer incubation time, higher temperature during incubation, higher temperature and longer duration of the heat induced epitope retrieval (slide pretreatment). The impact of the pH during slide pretreatment has variable effects and depends on the antibody and the target protein. All images and data shown here and in our image galleries are obtained by the manual protocol described below. Other protocols resulting in equivalent staining are described as well. Manual protocol Freshly cut sections should be used (less than 10 days between cutting and staining). Heat-induced antigen retrieval for 5 minutes in an autoclave at 121°C in pH 7,8 Target ... The expression of Arginase-1 in hepatic and extra-hepatic cancers needs to be evaluated to comprehensively assess the diagnostic utility of arginase-1 immunohistochemistry. The prognostic role of arginase expression levels in hepatocellular and squamous cell carcinomas are not clarified yet. There are two ways, how the specificity of antibodies can be documented for immunohistochemistry on formalin fixed tissues. These are: 1. comparison with a second independent method for target expression measurement across a large number of different tissue types (orthogonal strategy), and 2. Comparison with one or several independent antibodies for the same target and showing that all positive staining results are also seen with other antibodies for the same target (independent antibody strategy). For the antibody MSVA-511R specificity is documented by the strong concordance of the immunostaining with RNA expression data derived from the Human Protein Atlas (HPA) RNA-seq tissue dataset , the FANTOM5 project, and the Genotype-Tissue Expression (GTEx) project which are all summarized in the Human Protein Atlas (Tissue expression Arginase-1) . The RNA data show predominant arginase-1 RNA expression in the liver and much weaker expression in granulocytes and skin. These observations large...
