Abstract

BACKGROUND
The proto-oncogene c-kit encodes a transmembrane tyrosine kinase growth factor receptor. Studies have shown that c-kit is highly expressed in normal breast epithelium, but expression is decreased in primary breast cancer. Cyclooxygenase-2 (COX-2) is an inducible enzyme that converts arachidonic acid to prostaglandins. Expression of COX-2 has been reported in malignant tumors including breast cancer. We evaluated the expression of c-kit and COX-2 in benign and malignant lesions of the breast to assess the roles of these proteins in cancer initiation and progression.
METHODS
We characterized 20 benign lesions, 20 intraductal carcinomas and 70 invasive breast carcinomas. Immunohistochemical staining for c-kit and COX-2 was performed.
RESULTS
Expression of c-kit was detected in 75% of the benign breast lesions, 40% of the intraductal carcinomas and 10% of the invasive carcinomas. COX-2 expression was observed in 80% of the benign lesions, 70% of the intraductal carcinomas and 52% of the invasive carcinomas. Expression of c-kit was significantly correlated with tumor size (p=0.02). COX-2 expression was significantly correlated with negative expression of estrogen receptor and progesterone receptor (p=0.02, p=0.04), Her-2/neu expression (p=0.008) and the high proliferation index (p=0.0002).
CONCLUSIONS
Our results suggest that c-kit and COX-2 might be involved in malignant transformation of the mammary epithelium and tumor progression. It is suggested that c-kit and COX-2 can be used as predictive markers and therapeutic targets.

• Keywords: Breast cancer;c-kit;COX-2