title: Expression of carbonic anhydrase IX suggests poor outcome in rectal cancer.
abstract: The aim of the study is to assess the value of carbonic anhydrase isozyme IX (CA IX) expression as a predictor of disease-free survival (DFS) and disease-specific survival (DSS) in rectal cancer treated by preoperative radio- or chemoradiotherapy or surgery only. Archival tumour samples from 166 patients were analysed for CA IX expression by three different evaluations: positive/negative, proportion of positivity and staining intensity. The results of immunohistochemical analysis were confirmed by demonstrating CA IX protein in western blotting analysis. Forty-four percent of the operative samples were CA IX positive, of these 34% had weak and 66% moderate/strong staining intensity. In univariate survival analysis, intensity of CA IX expression was a predictor of DFS (P=0.003) and DSS (P=0.034), both being markedly longer in tumours with negative or weakly positive staining. In multivariate Cox model, number of metastatic lymph nodes and CA IX intensity were the only independent predictors of DFS. Carbonic anhydrase isozyme IX intensity was the only independent predictor of DSS, with HR=9.2 for dying of disease with moderate-intense CA IX expression as compared with CA IX-negative/weak cases. Negative/weak CA IX staining intensity is an independent predictor of longer DFS and DSS in rectal cancer.
authors.affiliation: Department of Oncology and Radiotherapy, Turku University Hospital, Savitehtaankatu 1, PB 52, Turku FIN-20521, Finland. eija.korkeila@tyks.fi
authors.forename: E
authors.initials: E
authors.lastname: Korkeila
authors.forename: K
authors.initials: K
authors.lastname: Talvinen
authors.forename: P M
authors.initials: PM
authors.lastname: Jaakkola
authors.forename: H
authors.initials: H
authors.lastname: Minn
authors.forename: K
authors.initials: K
authors.lastname: Syrjänen
authors.forename: J
authors.initials: J
authors.lastname: Sundström
authors.forename: S
authors.initials: S
authors.lastname: Pyrhönen
mesh_terms: D000368:Aged; D000951:Antigens, Neoplasm / Q000032:analysis*; D001706:Biopsy; D000071231:Carbonic Anhydrase IX; D002256:Carbonic Anhydrases / Q000032:analysis*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D011379:Prognosis; D016016:Proportional Hazards Models; D012004:Rectal Neoplasms / Q000201:enzymology* / Q000401:mortality* / Q000628:therapy
chemical_list: D000951:Antigens, Neoplasm; C089226:CA9 protein, human; D000071231:Carbonic Anhydrase IX; D002256:Carbonic Anhydrases