Significance of the Expression of p27(Kip1) Protein in Human Breast Cancer / 한국유방암학회지

ABSTRACT

PURPOSE: p27(Kip1) is a member of the Cip/Kip family of cyclin-dependent kinase inhibitors. It binds to a variety of cyclin/CDK complexes, inhibits kinase activity and blocks the cell cycle as a negative regulator. Reduced p27(Kip1) expression has been reported to be a significant predictor of poor survival in numerous human breast cancers. We executed p27(Kip1) protein assay in primary breast cancer and compared these result with known prognostic parameters. METHODS: Immunohistochemical assay was performed on tissue microarrays from 183 patients with breast cancer to evaluate the biologic and clinical significance of p27(Kip1) expression. RESULTS: Decreased p27(Kip1) expression was significantly associated with clinical stage (P=0.027), low nuclear grade (P<0.001), high histologic grade (P<0.001), high score mitotic index (P<0.001), increased Ki67 labeled index (P=0.006) and negative estrogen receptor status (P=0.0024). In survival analysis, p27(Kip1) was useful to predict disease- free survival (P=0.0106) and overall survival (P=0.0154) of the patient after surgery followed by chemotherapy or radiation therapy. CONCLUSION: Reduced expression of p27(Kip1) protein was as sociated with biologically aggressive phenotype of breast cancer and was an useful to predict patient outcome.