Objective: To investigate the expression of cyclin-dependent kinase inhibitor p27kip1 in renal cell carcinoma and its clinical significance.
Methods: The expressions of p27kip1 mRNA and protein were evaluated using reverse transcription polymerase chain reaction (RT-PCR), Western blotting and immunohistochemistry with tissue chip technique in renal cell carcinoma (RCC) tissues, adjacent tissues and 786-0 cell line. The relationship between the expression of p27kip1 and the tumor size, the clinical stage, pathological type and stage were evaluated, and the results by the 3 methods were analyzed to evaluate the relationship between the mRNA and protein of p27kip1.
Results: The expression of p27kip1 protein (detected by immunohistochemistry and Western blotting) in RCC tissue was significantly lower than that in the adjacent normal tissues (P<0.05). The expression of p27kip1 mRNA (by RT-PCR) showed no significant difference between the two groups. p27kip1 protein expression was found to be inversely correlated to the tumor grade and clinical stage (P<0.05). Western blotting and immunohistochemistry showed a high coincidence rate in the detection of P27kip1 protein expression in RCC samples (P<0.001, K=0.828).
Conclusion: p27kip1 mRNA expression shows no difference between RCC and normal tissues, while the protein expression is significantly lower in the cancer tissues, suggesting a regulatory mechanism of p27kip1 expression at the transcriptional level. Low expression of p27kip1 protein may promote the development and progression of RCC. p27kip1 protein may serve as a diagnostic and prognostic marker of RCC.