[200] Expression of IMP3 in Primary and Metastatic Breast Ductal Adenocarcinomas

MC Hure, Z Jiang, D Lu. University of Massachusetts Medical Center, Worcester, MA

Background: IMP3 is a RNA-binding protein and involved in multiple critical biological processes including RNA trafficking and stabilization, cell growth, and cell migration. We have shown that IMP3 is a novel molecular marker that predicts metastasis for renal cell carcinomas and urothelial carcinomas. The goal of this study is to compare IMP3 expression in primary and metastatic breast ductal carcinomas.
Design: 54 patients with breast ductal carcinomas were selected. They had surgery and follow-up at University of Massachusetts Medical Center. At the time of study, 24 cases were primary invasive ductal adenocarcinomas and 30 were metastatic ductal adenocarcinomas. Immunohistochemical stains were performed on paraffin-embedded tumor specimens using mouse monoclonal antibody specific for IMP3 (L523S, Corixa, Seattle, Wash) and our previously published protocols. The results were independently reviewed by two pathologists. Then, the association of IMP3 expression with patients' metastatic status was analyzed.
Results: In primary ductal adenocarcinomas, 2 out of 24 cases (8%) showed IMP3 overexpression while 14 out of 30 (48%) metastatic ductal adenocarcinomas had IMP3 overexpression (p<0.005). No IMP3 expression was found in adjacent benign tissues.

Table 1

	IMP3 +	IMP3 -
Primary tumor	2 (8%)	22 (92%)
Metastatic tumor	14 (48%)	16 (52%)

Conclusions: In contrast to normal breast tissue, we demonstrated that some breast ductal adenocarcinomas have high expression level of IMP3. The percentage of cases with such IMP3 expression increased 6 folds in metastatic carcinomas compared to the primary. These suggest that IMP3 is a potential prognostic biomarker to predict possible metastasis of breast ductal adenocarcinoma.
Category: Breast

Monday, March 9, 2009 1:00 PM

Poster Session II # 54, Monday Afternoon