TGF-alpha Expression During Breast Tumorigenesis
Abstract
Transforming Growth Factor-alpha (TGFalpha) is an oncogenic growth factor that drives estrogen-independent breast tumor proliferation via an autocrine loop. It's receptor, Epidermal Growth Factor Receptor (EGFR), is a proto-oncogene that may be overexpressed in some breast tumors. Normal breast TGFalpha and EGFR are expressed in an estrogen-dependent cell specific manner. To determine whether these oncogenes are important in the early stages of tumorigenesis, we compared the TGFalpha mRNA and protein expression in normal epithelium and tumor cell lines and examined the expression of TGFalpha and EGFR mRNA and protein expression in normal epithelium, proliferative breast disease, and carcinoma in situ. Breast cancer cell lines expressed primarily the expected 4.6 kb message. No evidence of splice variants was detected. Interestingly, protein expression from freshly isolated normal and tumor epithelium expressed primarily the soluble form of TGFalpha while the cell lines expressed the transmembrane form. This suggests that tissue culture may affect the normal regulation of this protein. TGFalpha protein expression in archival human tissues was constant during progression from benign to invasive disease. However, EGFR expression increased at the stage of proliferative breast disease, suggesting that increased EGFR expression is an important early event in the progression towards invasive disease.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1998
- Accession Number
- ADB240188
Entities
People
- Kevin Taylor
Organizations
- University of Cincinnati