RHODANESE AND ARGINASE ACTIVITY IN NORMAL AND CANCEROUS TISSUES OF HUMAN BREAST, ESOPHAGUS, STOMACH AND LUNG

Background and Objectives-Differences in the activities or concentration of certain enzymes in cancerous cells and their normal counterparts have been well documented. The purpose of this investigation was to determine and compare the activities of arginase and rhodanese in selected normal and cancerous human tissues. Methods-Cancerous tissue specimens were obtained from surgically resected organs and normal tissues were obtained from fresh frozen corpses in the Forensic Medicine Center, Shiraz, Iran. Rhodanese was assayed by the modified method of Sorbo and arginase activity was based on urea determination. Results-In most cases, the activity of arginase in the cancerous tissues was higher than the normal tissues, but in the stomach cancer, the increase was significant (p<0.05). The comparison between the activity of rhodanese in the normal and cancerous tissues revealed variable results; the activity was higher in the breast cancer group while it showed significantly (p<0.05) reduced activity in the lung cancer. Conclusion-The results presented in this study indicated that arginase activity was higher in the cancerous tissues than their normal counterparts and this might be consistent with the role of arginase in ornithine biosynthesis. Different patterns of rhodanese activity in the malignant tissues and its reduced activity especially in the lung cancer has no satisfactory explanation in the medical literature.