The expressions ofp27Kip1 (p27) and p21waf1 (p21) cyclin-dependent kinase inhibitors and p53 were examined in a series of 170 node-negative breast carcinomas (NNBCs) to evaluate their prognostic significance. Low nuclear (p27TN) and cytoplasmic (p27TC) p27 expressions were noted in 66% and 81% of NNBCs, respectively. p21 and p53 overexpressions were detected in 56% and 26%, respectively. Low p27TN was significantly associated with high grade (p=0.001), age < or = 50 years (p=0.01), negative hormone receptors (p<0.001), low p27TC (p<0.001) and p53 overexpression (p=0.02). Low p27TC was associated with negative hormone receptors (p<0.001). p53 overexpression was associated with high grade (p<0.001) and negative hormone receptors (p<0.001). p21 overexpression, although not correlated with the examined parameters, was associated with increased disease-free survival in univariate analysis. In multivariate analysis, p27TN, p27TC, p21 and p53 were not associated with disease-free survival or overall survival. These findings argue against the prognostic value of p27, p21 and p53 in NNBC.