Tamoxifen-induced DNA adducts in endometrial samples from breast cancer patients

Tamoxifen-induced DNA adducts were analyzed with the (32)P-postlabeling method using high-performance liquid chromatography (HPLC)-radioactivity detection from endometrial tissue of breast cancer patients and controls. Liver DNA from tamoxifen-treated rats was used as a positive standard. In blind analysis, five of the seven samples from tamoxifen-treated patients showed DNA adducts; none of the five controls were positive. The identity of the tamoxifen adduct was confirmed by using different chromatographic systems, isolating the HPLC fractions and running them on TLC, with or without spiked rat liver samples. The level of adducts in the treated patients was 2.7 adducts/10(9) nucleotides in the HPLC analysis.