EXPRESSION OF THE CDK INHIBITOR P27(KIP1) AND OXIDATIVE DNA DAMAGE IN RENAL CELL CARCINOMA

e16008 Background: Deregulation of the normal cell cycle is a frequent event in human tumors and plays an important role in malignant transformation. p27kip1 is a negative regulator of the G1 phase, is frequently lost in tumor cells and, in some cases, its alteration is coupled with oxidative DNA damage. Methods: We evaluated the expression of p27kip1 and the extent of endogenous oxidative DNA damage (by means of 8-hydroxydeoxyguanosine [8-OHdG] levels) by immunostaining in a series of 125 (median age 64[range23–86]yrs) renal cell carcinomas (RCCs); furthermore, the prognostic significance of their alterations was tested. Median values of expression were used as cut-off. p27kip1 expression was also evaluated by Western Blot in a second series of 34 fresh-frozen RCCs. Results: to date, median follow-up is 29[range 4 - 104] months. p27kip1expression was lost in a significant fraction of tumors (55%) with a median percentage of positive cells of 20% [range 0–60%). Loss of p27kip1 staining correlated with hig...