Expression of Transcription Factors [FOXA1-GATA3] in ER-Positive Node-Negative Breast Cancer.
Olga L Bohn, Gloria Carter, Adam Brusky, Rachel Jankowitz, Preeti Badve, Mamatha Chivukula. MetroHealth Medical Center, Cleveland, OH; Magee-Womens Hospital UPMC, Pittsburgh, PA
Background: In breast cancer, the determination of estrogen receptor (ER) status is essential in the decision on therapeutic strategies. Microarray analyses have shown that Forkhead box A1 (FOXA1) and GATA binding protein 3 (GATA3) are expressed in close association with ER alpha. The aim of this study is to investigate the relation between transcription factors FOXA1 and GATA3 expression and recurrence in a group of ER-positive, node negative breast cancer tumors.
Design: One hundred and nine (109) ER-positive node-negative cases were retrieved from the pathology database and included in this study. We determined ER, FOXA1 and GATA3 expression by immunohistochemistry. Nuclear staining of more than 10% of the tumor cells defined positive FOXA1 and GATA-3 using a cumulative H-score based on proportionality and intensity scores [H = 0-10 negative, 11-150 low, 151-250 intermediate, 251-300 high]. ER was considered positive if at least 1% of tumor cells showed nuclear expression (H-score >1).
Results: ER-positive tumors were more frequently Grade 2 (59.6%), followed by Grade 1 (20.1%) and Grade 3 (19.3%). The cases were classified according to the recurrence. No recurrence (NR) (Group-1) was seen in 57/109 cases (52.3%), locoregional recurrence (LRR)(Group-2) was observed in 13 cases (11.9%) and distant metastasis (DM)(Group-3) in 39 cases (35.8%). Overall, FOXA1 overexpression (moderate to strong nuclear expression) was detected in 99.08% of the ER-Positive cases (H score mean = 219.5) and GATA3 overexpression (moderate to strong nuclear expression) was detected in 98.15% cases (H score mean=213.1).
Conclusions: FOXA1 and GATA3 expression is directly associated to ER status and does not predict LRR or DM at this time. Correlation of FOXA1 and GATA3 expression with other predictor markers such as HER 2/neu and Ki-67are in progress.
Wednesday, March 2, 2011 1:00 PM
Poster Session VI # 17, Wednesday Afternoon