Antioxidant activity of blood plasma in individuals with neoplasms

In 3 groups of patients with neoplasms plasma antioxidant activity was measured by the yield of TBA-reactive products generated in lecithin-Fe(2+) model system. Patients with laryngeal, tongue, oropharyngeal, oral, and laryngopharyngeal tumors showed lower plasma antioxidant activity compared to patients with breast, lung, and bronchial cancer (p<0.005). In women with breast cancer plasma antioxidant activity increased with age (p<0.05). Possible mechanisms underlying these fluctuations are discussed. It is assumed that plasma antioxidant activity is relatively stable and modulates body resistance to tumor process.