Levels of 5-hydroxymethyl-2'-deoxyuridine in DNA from blood of women scheduled for breast biopsy.

Systemic oxidative stress is thought to contribute to risk of various cancers, including breast cancer. DNA repair ability also has been associated with breast cancer risk. In this work, we examined levels of oxidative DNA damage as an indication of breast cancer risk in women because oxidative DNA damage levels should reflect the net balance of oxidative stress and DNA repair ability. Levels of 5-hydroxymethyl-2'-deoxyuridine, one form of oxidative DNA damage, were measured in DNA from blood of women scheduled for breast biopsy. The blood samples analyzed included women whose biopsy results indicated invasive breast cancer, high-risk lesions (atypical hyperplasia or carcinoma in situ), or benign lesions. Mean levels of 5-hydroxymethyl-2'-deoxyuridine were significantly higher in blood of women who had high risk or invasive breast lesions versus women with benign lesions. If atypical hyperplasia or carcinoma in situ are precursor lesions for breast cancer, then these results suggest that oxidative DNA damage may be involved in the cancer process before invasive cancer develops.