RESUMO
BACKGROUND: Bone marrow (BM) is an important tissue in the generation of immunocompetent and peripheral blood cells. The precursors of hematopoietic cells in BM undergo continuous proliferation and differentiation and are highly vulnerable to acute and chronic oxidative stress. Little is known about the oxidant and antioxidant status in the BM of untreated patients with nonhematologic tumors. In this study, oxidative stress was evaluated in peripheral blood plasma (PBP) and BM plasma (BMP) from lung carcinoma (LC) and breast carcinoma (BC) patients. METHODS: The sample included 13 consecutive untreated LC patients, 15 BC patients, and 11 healthy controls. Luminol-dependent chemiluminescence was used to evaluate oxygen radical generation by peripheral blood neutrophils. Lipid oxidation, assessed by 2-thiobarbituric acid-reactive substances (TBARS), and alpha-tocopherol, beta-carotene, and total ubiquinol-10 levels were determined in PBP and BMP. RESULTS: In LC and BC patients, neutrophil chemiluminescence was higher (128% and 264%, respectively) than in controls (P < 0.05). In cancer patients, TBARS levels were higher in both PBP (51% and 243% for LC and BC patients, respectively) and BMP (66% and 305% for LC and BC patients, respectively) than in plasma from controls (P < 0.01). alpha-Tocopherol and total ubiquinol-10 levels were significantly lower in BMP from BC patients compared with controls. In BC patients, alpha-tocopherol content in PBP was significantly lower than in controls. CONCLUSIONS: Untreated cancer patients presented an imbalance between oxidant generation and lipid-soluble antioxidant levels in favor of the former.