Estrogen Receptor Expression in Atypical Hyperplasia and Its Association with Type of Atypia and Age
EG Barr-Fritcher, LC Hartmann, AC Degnim, SS Anderson, RA Vierkant, M Frost, DW Visscher, C Reynolds. Mayo Clinic, Rochester, MN; University of Michigan, Ann Arbor, MI
Background: Estrogen receptor (ER) expression is present in normal breast epithelium and premalignant breast lesions. Prior studies have shown that ER expression increases with age in normal breast epithelium; whereas no age association was seen in atypical hyperplasia and carcinoma in situ.
Design: ER expression was assessed immunohistochemically in archival sections from 246 women with atypical hyperplasia who had an open benign breast biopsy between 1967 and 1991. The ACISIII (Dako, Carpinteria, CA) was utilized to calculate ER expression (percent staining and staining intensity) in all atypical foci for each woman. Using multivariate linear regression, we examined associations of ER expression with age at biopsy, year of biopsy, indication for biopsy, type of atypia, number of atypical foci, involution status, and family history. Heterogeneity of breast cancer risk across levels of ER expression was also assessed, standardized to a control population (the Iowa SEER registry).
Results: Among the 246 women, 87 (35%) had ADH, 141 (57%) had ALH, and the remaining 18 (7%) had both ADH and ALH. About half (53%) were older than 55 years at diagnosis. Forty-nine (20%) developed breast cancer during a median follow up of 14.4 years. Multivariate analysis indicated that type of atypia, year of biopsy, and age at diagnosis were significant predictors of ER percent staining and intensity [P<0.05 (see Table 1)]. ER expression was increased in women with ADH and/or those over the age of 55. The relationship between ER (percent staining and intensity) and breast cancer risk in patients diagnosed with atypia was not significant (P=0.099 and P=0.118, respectively).
Multivariate Linear Regression Analysis for Predicting ER Mean Percent Staining and Intensity in Atypical Hyperplasia
|Variable||ER Mean Percent Staining (P-value)||ER Mean Intensity (P-value)|
|Year of Biopsy||0.002||0.001|
|Indication for Biopsy||0.706||0.868|
|Type of Atypia||<0.001||<0.001|
|Number of Foci||0.584||0.374|
Conclusions: This study suggests that ER expression is higher in ADH. Significance of year of biopsy could be due to age of tissue and its effect on immunohistochemistry. Contrary to previous reports, our results indicate that ER expression in atypical hyperplasia increases with age.
Tuesday, March 10, 2009 1:00 PM
Poster Session IV # 4, Tuesday Afternoon