title: Expression and diagnostic implications of carbonic anhydrase IX in several tumours with predominantly clear cell morphology.
abstract: OBJECTIVE
  High expression of carbonic anhydrase IX (CA IX) has been reported in clear cell renal cell carcinoma (ccRCC); few studies have reported CA IX expression in other tumours with predominantly clear cell morphology. The aim of study was to examine the expression and diagnostic implications of CA IX in these latter tumours.
  
  
  RESULTS
  An immunohistochemical study was performed of 159 tumours with predominantly clear cell morphology. The results showed that, in addition to primary (25/25) and metastatic (10/11) ccRCC, CA IX was also expressed in breast (2/2), pulmonary (3/5) and hepatic (1/4) clear cell carcinoma, urothelial carcinoma with clear cell change (3/6), clear cell meningioma (4/6) and ependymoma (2/3), haemangioblastoma (10/10), and clear cell hidradenoma (5/6). However, while strong and diffuse positivity for CA IX was observed in ccRCC, clear cell breast carcinoma, haemangioblastoma, and clear cell hidradenoma, the other cases showed predominantly focal positivity for CA IX. In particular, CA IX staining was often seen at the periphery of necrotic areas.
  
  
  CONCLUSIONS
  Our results indicate that strong and diffuse CA IX expression may be useful for differentiating ccRCC from several clear cell tumours, with the exception of clear cell breast carcinoma, haemangioblastoma, and clear cell hidradenoma.
authors.affiliation: Department of Pathology, the First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, China; Institute of Pathology and Pathophysiology, China Medical University, Shenyang, China.
authors.forename: Xu-Yong
authors.initials: XY
authors.lastname: Lin
authors.forename: Heng
authors.initials: H
authors.lastname: Zhang
authors.forename: Na
authors.initials: N
authors.lastname: Tang
authors.forename: Xiu-Peng
authors.initials: XP
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: En-Hua
authors.initials: EH
authors.lastname: Wang
authors.forename: Yu-Chen
authors.initials: YC
authors.lastname: Han
mesh_terms: D018250:Acrospiroma / Q000175:diagnosis / Q000201:enzymology; D000951:Antigens, Neoplasm / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001943:Breast Neoplasms / Q000175:diagnosis / Q000201:enzymology; D000071231:Carbonic Anhydrase IX; D002256:Carbonic Anhydrases / Q000378:metabolism*; D002292:Carcinoma, Renal Cell / Q000175:diagnosis / Q000201:enzymology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007680:Kidney Neoplasms / Q000175:diagnosis / Q000201:enzymology; D008113:Liver Neoplasms / Q000175:diagnosis / Q000201:enzymology; D008175:Lung Neoplasms / Q000175:diagnosis / Q000201:enzymology; D012509:Sarcoma / Q000175:diagnosis / Q000201:enzymology; D013544:Sweat Gland Neoplasms / Q000175:diagnosis / Q000201:enzymology
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; C089226:CA9 protein, human; D000071231:Carbonic Anhydrase IX; D002256:Carbonic Anhydrases
keywords: carbonic anhydrase IX; clear cell hidradenoma; clear cell renal cell carcinoma; clear cell tumours; haemangioblastoma