RESUMEN
BACKGROUND: p27Kip1 (p27) protein is an inhibitor of cyclin-dependent kinase complexes and prevents progression of cells from the G1- to the S-phase of the cell cycle. Decreased p27 expression has been shown to be associated with aggressive tumor behavior and decreased patient survival in numerous human malignancies. The aim of this study was to evaluate p27 expression in renal cell cancer and to assess its association with stage and grade as well as its relationship to patient outcome. MATERIALS AND METHODS: One hundred and fifty-four renal cell carcinoma specimens were evaluated for p27 expression by immunohistochemical staining. Immunohistochemical findings were correlated with tumor grade, tumor stage and patient outcome. RESULTS: A progressive loss of nuclear p27 expression was observed with increasing tumor grade. In poorly-differentiated tumors, p27 expression was significantly lower compared to well- and moderately-differentiated tumors (p = 0.025). p27 expression tended to decrease with increasing tumor stage, but the correlation was not statistically significant (p = 0.068). CONCLUSION: The present study suggests that renal cell carcinomas showed increased aggressiveness with loss of p27 expression. A longer follow-up period will demonstrate whether this cell cycle regulator will provide additional prognostic information in patients with renal cell carcinoma.