The present study evaluated the basal DNA damage and the cellular response to this damage induced by in vitro administration of Etoposide in lymphocytes donated by twenty untreated breast cancer (BC) patients and twenty age-matched healthy women. Micronucleus (MN) and alkaline Comet assays were performed in cultured peripheral blood lymphocytes (PBL) according to a standard protocol for in vitro treatment with various concentrations of Etoposide or a control. For the Comet Assay, three samples of cells were collected: T(0) (immediately preceding treatment of the cultures), T(1) (immediately after completion of the treatment) and T(2) (four hours after completion of the treatment). MN frequency in the BC group treated with 25 muM Etoposide (19.1 +/- 7.35) was significantly higher than the control (10.9 +/- 9.87) group. In the alkaline Comet Assay, both the BC group and the healthy women showed the ability to repair Etoposide-induced DNA damage within 4 hours of reincubation.
Keywords: Comet Assay; DNA repair; Micronucleus Test; breast cancer; etoposide.