Cancer Research Therapy and Control, cilt.5, sa.4, ss.301-306, 1998 (SCI-Expanded)
Activities of adenosine deaminase (ADA), cytidine deaminase (CD), xanthine oxidase (XO), hypoxanthine-guanine phosphoribosyl transferase (HGPRT), superoxide dismutase (SOD), catalase (CAT) and thiobarbituric acid reagent substance (TBARS) levels were measured in cancerous skin tissues, cancer free adjacent skin tissues and non-tumoral distant cutaneous tissues obtained from 9 patients with cutaneous carcinomas being basal cell carcinomas and squamous cell carcinomas. Increased ADA, decreased CD and XO activities along with unchanged HGPRT, SOD, CAT activities and TBARS levels were found in cancerous tissues when compared with cancer free adjacent tissue and non-tumoral distant tissues. These results suggested that increased ADA activity might also be a compensatory mechanism against the toxic effect of its substrate. Salvage pathway activity of purine and pyrimidine nucleotides were not changed in human cutaneous carcinomas. Free radical metabolizing enzyme activities and TBARS levels were not changed in cancerous tissue, which indicates that free radicals may not play a role in the etiology of human skin cancer and that skin cancer tissue is able to eliminate reactive oxygen species produced by several pathways.