[Purine metabolism in human tumors].

Levels of oxypurines (hypoxanthine and xanthine) and uric acid were measured in plasma and urine of tumor bearing patients (gastric and colon rectal tumors), and of subjects affected by non specific diseases. In both groups, an increase in plasma purine bases and a decrease of their excretion was observed as compared to healthy controls; no substantial variations concerning uric acid were found. Possible mechanisms inducing alterations of purine metabolism in so different conditions are discussed.