Down-regulation of p27 is a significant predictor of poor overall survivaland may facilitate metastasis in colorectal carcinomas

The p27 gene product has been shown to have prognostic significance in a ra nge of tumors. Down-regulation of p27 has also been implicated in loss of c ell adhesion in tumor cells. Our study aimed to investigate whether p27 exp ression was significantly correlated with overall survival of colorectal ca rcinoma patients in the Singapore population, which is pre dominantly Chine se. Staining was performed on 136 paraffin-embedded specimens collected bet ween 1991 and 1992 using an anti-p27 monoclonal antibody. Follow-up of pati ents was until time of death or for 5 years. There was a significant associ ation between overall survival and p27 expression for all specimens. Howeve r, there was no significant correlation between p27 expression and other cl inical features such as gender, age, tumor stage, differentiation, and site . When stratified by tumor stage, patients whose tumors exhibited higher me tastatic potential (stage III/IV) but had strong p27 expression had a media n survival that was 23 months longer than stage III/IV patients whose tumor s had no or weak p27 expression. Our results thus suggest that one potentia l mechanism of action of p27 is to suppress metastasis possibly through its involvement in cell adhesion. (C) 2000 Wiley-Liss, Inc.