Free Radicals and Breast Cancer

The authors of the articles, Douki et al. (2) and Ravanat et al. (3), were concerned primarily with the possibility ofDNA base oxidations in the formation of trimethysilyl derivatives for gas chromatography-mass spectrometry (GC-MS). The focus was not on our work and the authors did not attempt to duplicate our results or dispute our conclusions. In our studies of base changes in relation to breast cancer, we consistently compared control and test samples under identical conditions that favored the exclusion of oxygen. Ravanat et al. (3) found no fault with this approach, stating that