Alpha-methyl CoA racemase expression in renal cell carcinomas

• Published in: Human pathology 2006-06, Vol.37 (6), p.698-703
• Main Authors: Molinié, Vincent, Balaton, André, Rotman, Samuel, Mansouri, Douha, De Pinieux, Isabelle, Homsi, Toufik, Guillou, Louis
• Format: Article
• Language: English
• Subjects: Adenocarcinoma, Mucinous - enzymology; Adenocarcinoma, Mucinous - pathology; Adenoma, Oxyphilic - enzymology; Adenoma, Oxyphilic - pathology; Alpha-methyl CoA; Biological and medical sciences; Cancer; Carcinoma; Carcinoma, Papillary - enzymology; Carcinoma, Papillary - pathology; Carcinoma, Renal Cell - enzymology; Carcinoma, Renal Cell - pathology; Chromophobe renal cell carcinoma; Gene expression; Humans; Immunohistochemistry; Investigative techniques, diagnostic techniques (general aspects); Kidney Neoplasms - enzymology; Kidney Neoplasms - pathology; Kidneys; Medical sciences; Mucinous and spindle cell tumor; Nephrology. Urinary tract diseases; Oncocytoma; p504s; Papillary renal cell carcinoma; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; Proteins; Racemases and Epimerases - genetics; Racemases and Epimerases - metabolism; Renal cell carcinoma; Tumors; Tumors of the urinary system
• ISSN: 0046-8177; 1532-8392
• DOI: 10.1016/j.humpath.2006.01.012

Alpha-methyl CoA racemase (AMACR), a new molecular marker for prostate cancer, has been recently reported to be one of the most highly expressed genes in papillary renal cell carcinomas (RCCs). We tested the diagnostic usefulness of AMACR antibody in a series of 110 renal tumors: 53 papillary RCCs (33 type 1, 20 type 2); 25 conventional RCCs; 6 chromophobe RCCs; 9 oncocytomas; 5 mucinous tubular and spindle tumors; 2 urothelial carcinomas; 7 angiomyolipomas; and 2 Bellini carcinomas. Immunohistochemical staining was performed on formalin-fixed, paraffin-embedded tissue sections, with a primary prediluted rabbit monoclonal anti-AMACR antibody. Both type 1 and type 2 papillary RCCs exhibited cytoplasmic immunoreactivity for AMACR, with diffuse strong granular staining in 96.4% (53/55) of tumors, without correlation with type or nuclear grade. The 5 mucinous, tubular, and spindle cell carcinomas strongly expressed AMACR, and only 5 of 25 clear cell RCCs and 1 of 9 oncocytomas were focally reactive. The remaining 6 chromophobe RCCs, 5 urothelial carcinomas, and Bellini duct carcinomas showed no immunoreactivity for AMACR. Because high expression of AMACR is found in papillary RCCs (type 1 and 2) and in mucinous, tubular, and spindle cell carcinomas of the kidney, immunostaining for AMACR should be used in conjunction with other markers when histological typing of a renal tumor is difficult.