ACTIVITIES OF PURINE-PYRIMIDINE AND FREE-RADICAL METABOLIZING ENZYMESIN HUMAN CUTANEOUS CARCINOMAS

Activities of adenosine deaminase (ADA), cytidine deaminase (CD), xant hine oxidase (XO), hypoxanthine-guanine phosphoribosyl transferase (HG PRT), superoxide dismutase (SOD), catalase (CAT) and thiobarbituric ac id reagent substance (TBARS) levels were measured in cancerous skin ti ssues, cancer free adjacent skin tissues and non-tumoral distant cutan eous tissues obtained from 9 patients with cutaneous carcinomas being basal cell carcinomas and squamous cell carcinomas. Increased ADA, dec reased CD and XO activities along with unchanged HGPRT, SOD, CAT activ ities and TEARS levels were found in cancerous tissues when compared w ith cancer free adjacent tissue and non-tumoral distant tissues. These results suggested that increased ADA activity might also be a compens atory mechanism against the toxic effect of its substrate. Salvage pat hway activity of purine and pyrimidine nucleotides were not changed in human cutaneous carcinomas. Free radical metabolizing enzyme activiti es and TEARS levels were not changed in cancerous tissue, which indica tes that free radicals may not play a role in the etiology of human sk in cancer and that skin cancer tissue is able to eliminate reactive ox ygen species produced by several pathways.