An evaluation of cytosolic erythrocyte carbonic anhydrase and catalase in carcinoma patients: An elevation of carbonic anhydrase activity

Objectives: The antioxidant enzyme catalase and the CO2/HCO3− exchange enzyme carbonic anhydrase are both present in significant amounts in the cytosol of erythrocytes. The aim of the present study was to investigate whether these erythrocyte enzyme activities are altered in patients who have carcinoma. Design and methods: Cytosolic erythrocyte enzyme activities were measured in 108 cancer patients presenting with carcinoma at one of variable sites, prior to clinical treatment. These were compared with an age- and sex-matched control group of 31 healthy volunteers. Results: Mean (±SD) catalase activities did not differ significantly, i.e. 0.0035 (±0.0015) EU/ml in carcinoma patients vs. 0.0031 (±0.00075) EU/ml in controls. However, mean carbonic anhydrase activities of 204 (±91) EU/ml in the carcinoma patients were significantly higher than the 158 (±35) EU/ml in controls (P value of 0.0065). Conclusion: Cytosolic erythrocyte carbonic anhydrase levels may warrant further investigation as a potential peripheral marker in cancer.