Role of carbonic anhydrase 9 as diagnostic and prognostic marker in clear cell renal cell carcinoma: A single centre study

Abstract

Background: Carbonic anhydrase 9 (CA-9) is currently being evaluated as prognostic and predictive biomarker for clear cell renal cell carcinomas (ccRCC) and also aids in diagnosis, monitoring tumour progression and clinical outcome. Methods: Descriptive study wherein 100 cases of primary ccRCC and 50 controls tissues were evaluated for CA-9 by immunohistochemistry. Immunoreactivity scores and pattern of staining were correlated with Furhman grading, clinical staging and risk stratification. Results: 88% cases of ccRCC exhibited CA-9 immunopositivity wherein 20% nonclear cell category were positive exhibiting strong statistical correlation between CA-9 immnoexpression and ccRCC. Low grade tumours, lower stage grouping and low risk tumours (UCLA integrated clinical staging) exhibited strong to moderate positivity while high grade, high stage and high risk tumours were either negative or exhibited weak patchy positivity and association was statistically significant. Conclusion: CA-9 is a valuable diagnostic marker for ccRCC and its expression correlates with low grade low risk tumours with favourable prognosis.