SEATTLE The first and largest clinical trial of its kind confirms that a protein called p27 may be a valuable tool for predicting survival after a diagnosis of breast cancer.
The findings, by lead author Peggy Porter, M.D., of Fred Hutchinson Cancer Research Center, in collaboration with colleagues from nine other institutions, appear in the Dec. 6 issue of the Journal of the National Cancer Institute. More than a decade ago, Porter and colleagues at the Hutchinson Center identified p27, a protein that prevents cells from dividing. Since then, several population-based and clinical studies at the Hutchinson Center and elsewhere have indicated that abnormally low levels of this protein in tumor cells are associated with poor prognosis for breast and other cancers. This link suggests that p27 may be a useful clinical biomarker, or predictor, of breast-cancer survival. However, such attempts to determine the prognostic value of p27 have been limited by the fact that the women studied have not received uniform treatment, so it has been unclear whether certain treatments may impact the strength of p27 as a predictor of outcome.
Now, for the first time, researchers have confirmed the link between low p27 expression and decreased breast-cancer survival in a large randomized, controlled clinical trial of two standard chemotherapy drugs.
"Being able to look at the impact of p27 on breast-cancer outcome in a clinical setting in which all the women were treated similarly allows us to tease out the relationship between the expression of this protein and breast-cancer mortality. Until now, we haven't been able to look at this," said Porter, a member of the Hutchinson Center's Human Biology and Public Health Sciences divisions.
The researchers found that low p27 expression is associated with poor breast-cancer prognosis, particularly among women with hormone-receptor-positive tumors, which depend on the hormones estrogen and progesterone to grow. Specific
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Contact: Kristen Lidke Woodward
kwoodwar@fhcrc.org
206-667-5095
Fred Hutchinson Cancer Research Center
5-Dec-2006