Abstract
To compare the effects of ionising radiation on leukocytes from breast cancer patients and healthy subjects ex vivo, the level of NF-κB and the antioxidant enzymes manganese-containing superoxide dismutase (Mn-SOD), copper/zinc-containing superoxide dismutase (CuZn-SOD) and catalase (CAT) in combination with flow cytometric analysis of CD4+ lymphocytes was performed. The level of Mn-SOD protein was significantly increased in the breast cancer study group both before (P < 0.001) and after (P < 0.001) irradiation when compared with healthy subjects. Measurements in parallel indicated that the level of CAT protein was significantly higher in the breast cancer study group after irradiation (2 Gy [P < 0.001] and 9 Gy [P < 0.05]) when compared with healthy subjects. Although the initial number of lymphocytes in the blood of breast cancer patients was not different from healthy subjects, the percentage of apoptotic CD4+ cells was significantly (P < 0.001) lower both before and after irradiation indicating that cell culture conditions induced radioresistance of CD4+ cells in the blood of breast cancer patients. The data presented in this current study indicate that brief ex vivo culture of peripheral blood leukocytes potentiates oxidative stress imposed by a breast cancer tumour.