A clinicopathological study of p53, p21 (WAF1/CIP1) and cyclin D1 expression in human prostate cancers

A series of 66 prostate cancer samples were studied immunohistochemically for expression of p53, p21, a cyclin-dependent kinase inhibitor regulated by p53, and cyclin D1, a cell cycle regulatory protein. Twenty samples (30%) showed positive staining for p53, 14 (21%) for p21, and 20 (30%) for cyclin D1. p53 expression was correlated with a high Gleason score while p21 and cyclin D1 did not demonstrate any clear clinicopathological factors. A positive correlation between p53 and p21 expression was observed, however these samples with both positive immunoreactivity had no p53 mutation, suggesting the possibility that p53 may be wild-type and induce p21 expression, and/or p21 is likely to be induced by a p53-independent pathway.