According to a recent article published in The New England Journal of Medicine, a protein referred to as cyclin E appears to be a powerful predictor of survival in patients with breast cancer, particularly early-stage breast cancer.
The prognosis of breast cancer is often determined by the stage, or extent, of disease. Early-stage breast cancer refers to cancer that has not spread to distant sites in the body. A significant prognostic predictor of early-stage breast cancer is the presence or absence of cancer spread to axillary (under the arm) lymph nodes. However, approximately one-third of patients who do not have cancer spread to axillary lymph nodes will experience a recurrence of their disease following therapy, while one-third of patients who do have axillary spread achieve cancer-free survival at 10 years following therapy. Thus, more accurate methods of prognostic indication are needed to provide optimal therapeutic strategies for patients with early-stage breast cancer.
Researchers from the MD Anderson Cancer Center recently analyzed data from cancer specimens of nearly 400 patients with breast cancer. The specimens were analyzed for particular “markers” or proteins, including HER-2/neu status, estrogen/progesterone receptor status, cyclin D1, cyclin D3 and cyclin E to determine if an association existed between the presence of any of these proteins and long-term survival. The patients in this study were followed for approximately 6.4 years.
Cyclin E is a protein that is involved in the regulation of cellular replication. Previous studies have indicated that cyclin E affects cellular behavior; however, results have provided mixed results regarding the association between cyclin E and long-term outcomes of patients with breast cancer. Researchers in this study utilized a different laboratory method, called Western blotting, than in previous studies in an attempt to provide more accurate results.
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The majority (92%) of patients in this study had stages I,II or III breast cancer. Patients with more advanced disease tended to have higher levels of cyclin E. High levels of cyclin E were the most powerful predictor of cancer-specific survival, including spread to lymph nodes. In this study, 112 patients had been diagnosed with stage I breast cancer. Of these patients, 104 had low levels of cyclin E; none of whom had died from breast cancer within 5 years from their diagnosis. However, the 12 stage I patients who had high levels of cyclin E had all died from breast cancer within 5 years from diagnosis.
These researchers concluded that high levels of cyclin E, as obtained by Western blotting assay, may provide an invaluable clinical marker in the determination of the risk of cancer spread and death due to breast cancer. Patients with high levels of cyclin E may benefit from more aggressive therapies and close monitoring, while patients with low levels of cyclin E may not need intensive therapy and thus be spared from side effects of unnecessary treatment. Further large clinical trials evaluating levels of cyclin E and outcomes of breast cancer patients are warranted. Patients diagnosed with breast cancer may wish to speak with their physician about the risks and benefits of testing for cyclin E or participation in a clinical trial further evaluating prognostic indicators for long-term survival. Two sources of information regarding ongoing clinical trials include the National Cancer Institute (cancer.gov) and www.eCancerTrials.com eCancerTrials.com also provides personalized clinical trial searches on behalf of patients.
Reference: Keymoarsi K, Tucker S, Buchholz T, et al. Cyclin E and survival in patients with breast cancer.
The New England Journal of Medicine. 2002;347:1566-1575.
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