Elevated levels of p27, p21 and cyclin D1 correlate with positive oestrogen and progesterone receptor status in node-negative breast carcinoma patients

The search for better prognostic indicators and new treatment modalities in node-negative breast carcinoma patients is important. The aim of this stud y was to determine the immunohistochemical expression of central cell regul ator proteins in relation to hormone receptor status, tumour-cell different iation and prognosis. We investigated the immunoreactivity of p27, p21, cdk 4, cyclin D1 and p53 in 77 node-negative breast carcinomas, with long-term follow-up (mean 163 months; range 20-227). Nuclear staining for p27 was see n in 87% of the carcinomas, for cdk4 in 92%, for p21 in 68%, for cyclin D1 in 58% and for p53 in 18%. Oestrogen receptor (ER) and progesterone recepto r (PgR) nuclear staining was seen in 69% and 65% of the tumours, respective ly. No correlation between the levels of p21 and p53 was observed. P21 over expression was, however, associated with positive ER status. Elevated level s of p27 and cyclin D1 correlated with positive hormone status (both ER and PgR). We did find a significant correlation between p27 and cyclin D1 and histological grade of the tumours, with extensive positive immunostaining o f p27 and cyclin D1 in well-differentiated carcinomas. The only significant prognostic factor in our series was histological grading. Ten-year relapse -free survival was significantly prolonged in patients with histological gr ade I tumours versus histological grade Il and III tumours. Our results sug gest that the expression of p27 and cyclin D1 is closely linked to hormone receptor status in breast carcinomas and to tumour differentiation, a findi ng that may be of importance in the treatment of hormone-dependent tumours.