title: CA9 expression as a prognostic factor in renal clear cell carcinoma.
abstract: BACKGROUND
  We investigated whether CA9 protein could be used as a prognostic tumor marker as well as a diagnostic biomarker in renal clear cell carcinoma.
  
  
  METHODS
  Nephrectomy specimens from 92 patients were used in this study. 80 of these were renal cell carcinomas, 10 adenomas and 2 oncocytomas. Of the renal cell carcinomas, 67 were clear cell carcinomas. Immunohistochemical analysis using CA9 monoclonal antibody (M75) was performed on paraffin-embedded specimens. CA9 staining was correlated with tumor stage, grade, lymph node involvement, distant metastasis and cumulative survival time.
  
  
  RESULTS
  CA9 was present in 91.2% of clear cell carcinomas. Low staining was a poor prognostic factor, and conversely high staining a good prognostic one. CA9 expression was found to be the best prognostic factor when compared with T stage and grade. Even in low-grade and stage tumors, the presence of low expression correlated with lowered survival times.
  
  
  CONCLUSIONS
  On the basis of our study, CA9 is a significant molecular marker in renal clear cell carcinomas. Decreased CA9 expression is independently associated with poor survival. CA9 can be used to predict clinical outcome and identify high-risk patients in need for adjuvant immunotherapy and CA9 targeted therapies.
authors.affiliation: Department of Urology, Cukurova University Medical Faculty, Adana, Turkey. bsoyupak@cu.edu.tr
authors.forename: Bülent
authors.initials: B
authors.lastname: Soyupak
authors.forename: Seyda
authors.initials: S
authors.lastname: Erdoğan
authors.forename: Melek
authors.initials: M
authors.lastname: Ergin
authors.forename: Gülsah
authors.initials: G
authors.lastname: Seydaoğlu
authors.forename: Bariş
authors.initials: B
authors.lastname: Kuzgunbay
authors.forename: Zühtü
authors.initials: Z
authors.lastname: Tansuğ
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000951:Antigens, Neoplasm / Q000096:biosynthesis*; D000071231:Carbonic Anhydrase IX; D002256:Carbonic Anhydrases / Q000096:biosynthesis*; D002292:Carcinoma, Renal Cell / Q000378:metabolism*; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies
chemical_list: D000951:Antigens, Neoplasm; C089226:CA9 protein, human; D000071231:Carbonic Anhydrase IX; D002256:Carbonic Anhydrases