Cyclin E, a Potential Prognostic Marker in Breast Cancer.
Abstract
We have examined tumor specimens from 400 breast cancer patients, comparing the changes of cyclin E expression with seven other established tumor markers as well as patient outcome. Altered expression of cyclin E was observed in 90% of all breast cancers with poor prognosis where patients either died of breast cancer or were still with cancer at the last contact date. Similarly in 85% of all breast cancer patients where cyclin E was either not altered, or its alteration was minimal, patients had a favorable prognosis. We also examined the expression of cyclin D and PCNA in the same group of patients and found while cyclin D was overexpressed in 4O% of all cases examined, such overexpression was not linked to poor prognosis or to cyclin E overexpression. Lastly, overexpression of PCNA, indicative of highly proliferative cancer, was not sufficient to account for such high association of cyclin E expression to poor prognosis. These analysis revealed that cyclin E protein is the most consistent marker for determining the prognosis of early-stage node-negative ductal carcinoma, providing very strong evidence for the use of cyclin E as a novel prognostic marker for breast cancer. The alteration of cyclin E in breast cancer has been further characterized and reveals that while cyclin E is cell cycle regulated in normal cells, it is present constitutively and in an active complex in synchronized populations of breast cancer cells. Since cyclin E is active throughout the cell cycle in tumor and not normal cells, it functions redundantly and activates substrates in only tumor cells.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1997
- Accession Number
- ADA341275
Entities
People
- Khandan Keyomarsi