Expression of p27Kip1 protein in transitional cell carcinoma of the upper urinary tract

Abstract

The expression of p27Kip1, a negative regulator of the cell cycle, has been reported to correlate with the biological behavior and prognosis of several tumors. However, its prognostic importance in transitional cell carcinoma of the upper urinary tract (TCC-UUT) has not previously been investigated. We investigated p27Kip1 protein expression using immunohistochemistry in 132 cases of TCC-UUT and also its relation to proliferating cell nuclear antigen (PCNA) immunoreactivity, p53 oncoprotein immunoreactivity, clinicopathologic parameters, and clinical outcome. A positive expression of p27Kip1 protein was recognized in 94.7% of the samples and was apparent within tumor nuclei. In the normal urothelium, its expression was identified in all cell layers. A positive expression of p53 oncoprotein was recognized in 27.2% of the patients. The PCNA index was 7.4 to 93.1% (mean, 66.4%). Examination of the relationships between the expression of p27Kip1 protein and clinicopathologic findings, PCNA index, and the expression of p53 oncoprotein revealed that the expression of p27Kip1 protein decreased significantly with stage and grade. In a univariate analysis of disease-free and overall survival rates, no correlation was found between the expression of p27Kip1 protein and prognosis. The expression of p27Kip1 protein appears to be of little or no value in informing the prognosis in TCC-UUT.