The relationship of single-strand breaks in DNA to breast cancer risk and to tissue concentrations of oestrogens.

CONTEXT: Clinical study of breast cancer patients in Chicago, IL, USA.

OBJECTIVE

Ascertain the utility of measurements of single-strand breaks (SSB) in DNA for assessment of breast cancer risk.

METHODS

Fine-needle aspirates of the breast, SSB by nick translation, percent breast density (PBD), Gail model risk, cumulative methylation index (CMI), enzymes of DNA repair and tissue antioxidants.

RESULTS

DNA repair enzymes and 4-hydroxyestradiol were negatively associated with SSB; CMI and PBD were positively associated.

CONCLUSIONS

Quantitative measurement of SSBs by this procedure indicates the relative number of SSBs and is related to promoter methylation, antioxidant availability and percent breast density.