Prevalence of aneuploidy, overexpressed ER, and overexpressed EGFR in random breast aspirates of women at high and low risk for breast cancer.

Breast tissue biomarkers which accurately predict breast cancer development within a 10 year period in high risk women are needed but currently not available. We initiated this study to determine 1) the prevalence of one or more breast tissue abnormalities in a group of women at high risk for breast cancer, and 2) if the prevalence of biomarker abnormalities is greater in high risk than in low risk women. Eligible high risk women were those with a first degree relative with breast cancer, prior breast cancer, or precancerous mastopathy. Low risk women were those without these or other major identifiable risk factors. Ductal cells were obtained via random fine needle aspirations and cytologically classified. Biomarkers included DNA ploidy, estrogen receptor (ER), and epidermal growth factor receptor (EGFR). The prevalence of DNA aneuploidy was 30%, overexpression of ER 10%, and overexpression of EGFR 35%, in the 206 high risk women whose median 10 year Gail risk (projected probability) of developing breast cancer was 4.5%. The prevalence of aneuploidy and overexpressed EGFR was significantly higher in the high risk women than in the 25 low risk controls (p < 0.002), whose median 10 year Gail risk was 0.7%. The difference in the prevalence of ER overexpression between high and low risk groups was not statistically significant (p = 0.095). This may be due to the low prevalence of overexpressed ER and the small number of controls. A significant difference was noted in the prevalence of one or more abnormal biomarkers between the high risk and low risk women (p < 0.001). A large prospective trial is needed to determine if one or more of these biomarkers, is predictive of breast cancer development.