Role of Estrogen Receptor Variants in Tumorgenesis of Human Breast Cancer
Abstract
In order to determine whether differences exist in expression of estrogen receptor (ER) variant mRNAs between normal and tumor breast tissues, we have analyzed by reverse transcription-polymerase chain reaction (RT-PCR) ER variants mRNA expression in matched normal breast tissue and breast tumor components. A higher expression of exon 5-deleted, and of ERC4 variants in the tumor component compared to the normal counterpart of matched samples was seen whereas a higher expression of exon 3-deleted ER variant in the normal tissue was observed. This is consistent with previous observations made on independent samples. We have described the presence within normal breast as well as in breast tumor tissues of several variant forms of ER-beta mRNA deleted in exon 5, exon 6, exon 5+6 or exon 8 sequences. The balance between some of these different ER-beta isoforms was modified during breast tumorigenesis and tumor progression. We also showed that a higher ER-alpha/ER-beta ratio was observed in the breast tumors compared with their matched normal breast tissues. This increase was attributed to an increase in ER-alpha mRNA expression and a lower ER-beta mRNA expression in the tumor compared with that of the normal component in some ER+ cases.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1999
- Accession Number
- ADA381387
Entities
People
- Etienne Leygue
Organizations
- University of Manitoba