[229] Aldehyde Dehydrogenase 1 (ALDH1) Expression in Non-Lobular Breast Carcinomas in African American Women

Tammey J Naab, Ashwini K Esnakula, Luisel J Ricks-Santi, Yasmine Kanaan, Bert Gold. Howard University Hospital, Washington, DC; Frederick National Laboratory for Cancer Research, Frederick, MD

Background: Stem-cell like features have been linked to ALDH1 expression in subpopulations of normal and neoplastic breast epithelial cells. ALDH1 expression is associated with breast carcinomas having a poor prognosis. Previous studies have linked the expression of ALDH1 with triple negative breast cancers, which are more common in younger African-American women. The objective of our study is to correlate the immunohistochemical expression of ALDH-1 in the four major subtypes of breast carcinoma (luminal A, luminal B, HER2 positive, and Triple Negative) and other clinicopathological factors in African American women.
Design: Tissue microarrays (TMAs) were constructed from optimally-fixed formalin-fixed, paraffin-embedded tumor blocks from primary breast ductal carcinomas in 203 African-American females. Two separate 1mm cores represented each case. Tumors were subtyped based on expression of ER, PR, HER2, vimentin and 34βE12. Immunohistochemical evaluation for ALDH1 was performed using mouse monoclonal antibody (3E9, Sigma-Aldrich, USA). The sections were evaluated for the intensity of reactivity (0-3) and the percentage of reactive cells; and an H-score was derived from the product of these measurements. Cases were categorized as having negative (score=0) or positive (score>0) ALDH1 cytoplasmic expression in tumor cells. Bivariate analysis was done via χ2 analysis and survivability data was calculated via the generation of Kaplan-Meier curves (SPSS v19). Statistical significance was assumed if P < 0.05.
Results: In our study, Luminal A was 43.8%, Luminal B 14.4%, HER2 8.5%, and Triple Negative 33.3% of which 51% were basal-like phenotype. ALDH1 positivity was associated with high grade (0.03) and Her2 positivity (p=0.057). Expression was not associated with age, stage, or survival. In our study, ALDH1 was expressed in 40% of all the cases, but did not show a correlation with triple negative breast cancers, and was expressed in several ER+ breast cancers.
Conclusions: Mammary stem cells, identified by cells expressing the marker aldehyde dehydrogenase 1 (ALDH1), have been associated with malignant transformation of breast tissue and have been reported in a subset of triple negative breast cancers. ALDH1 expression was found in 40% of breast cancers in our study with expression in all subtypes. We found statistically increased expression of ALDH1 in cases with HER2 positivity and high grade histology.
Category: Breast

Wednesday, March 6, 2013 1:00 PM

Poster Session VI # 6, Wednesday Afternoon

 

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