Increased H2O2 level in exhaled breath condensate in primary breast cancer patients.

Purpose: This study was designed to assess exhaled hydrogen peroxide (H(2)O(2)), blood serum antioxidant capacity, and tumor necrosis factor-alpha (TNFalpha) in primary breast cancer (PBC).

Methods: The study included 34 consecutive, non-smoking PBC patients (aged 62.5 +/- 13.