Tissue expression of Carbonic Anhydrase IX (CA IX) in different Gleason grades of prostate cancer

Lisa G Smyth (1) , Gillian O'Hurley (1) , Anthony Ogrady (1) , John Fitzpatrick (1) , Elaine Kay (1) , William Watson (1)

1 Surgical Laboratory

Introduction: Tumour hypoxia is associated with over 70% of solid tumours including prostate and colorectal cancer. Hypoxia promotes tumour progression and resistance to treatment. Carbonic anhydrase IX (CA IX) is an endogenous marker of hypoxia. It is expressed in lung and renal cell carcinomas and is associated with a poor prognosis. CA IX plays an important role in maintaining pH levels in the highly metabolically active cancer cell. The expression of CA IX in prostate cancer has not previously been investigated. Materials & Methods: Immunohistochemistry was used to examine CA IX expression in 59 patients, using tissue microarrays (TMAs) and full sections of benign prostatic hyperplasia, surrounding stroma and prostate adenocarcinoma. Cores reviewed included 189 benign prostatic hyperplasia, 130 Gleason grade 3, 93 Gleason grade 4, 40 Gleason grade 5. CA IX expression in colorectal cancer and HIF 1α in prostate cancer acted as positive controls. Results: There was only occasional cell staining for CA IX expression. Discussion: Although prostate cancer is a hypoxic tumour it does not express CA IX. This implies it relies on alternative pathways for maintaining pH balance in cancer. These studies would indicate that CA IX is not a suitable marker of hypoxia in prostate cancer.

Mots clés: hypoxia; prostate cancer; carbonic anhydrase IX

Lisa G Smyth, Gillian O'Hurley, Anthony Ogrady, John Fitzpatrick, Elaine Kay, et al.. Tissue expression of Carbonic Anhydrase IX (CA IX) in different Gleason grades of prostate cancer. Prostate Cancer and Prostatic Diseases, 2009, n/a (n/a), pp.n/a-n/a. ⟨10.1038/pcan.2009.58⟩. ⟨hal-00495783⟩