Prognostic significance of p27(Kip1) expression in colorectal cancer: A clinico-pathological characterization

This study has evaluated the expression of the cyclin-dependent kinase inhi bitor p27(Kip1) in 89 colorectal cancers (CRCs) using immunohistochemistry and has related p27 levels to clinico-pathological characteristics, tumour cell proliferation, and the expression of other GIS transition regulator! p roteins, Low levels of p27 were common in CRCs: 11 per cent of the tumours expressed very low levels and 44 per cent had p27 labelling indices (LIs) b elow 50 per cent, Except for depth of tumour invasion. no significant corre lation,vas found between p27 expression and Dukes' stage, differentiation, growth pattern, tumour type or lymphocytic infiltration. Interestingly, tum ours expressing low or very low p27 LIs were predominantly found in the rig ht colon (p=0.026). Expression of p27 was a strong predictor of survival, b oth in univariate and in multivariate survival analyses; patients with tumo urs of p27 LI less than 50 per cent had an impaired prognosis (p=0.0069). p 27 expression did not correlate with tumour cell proliferation, or with exp ression of cyclin D1 or the retinoblastoma protein (pRb), These findings su pport the view that p27 not merely. controls cell cycle progression, but mi ght be associated with other mechanisms responsible for aggressive tumour b ehaviour in colorectal cancer. Copyright (C) 1999 John Wiley & Sons, Ltd.