In this study, tumour tissue samples of 85 primary breast cancer patients were evaluated for phosphatase and tensin homolog deleted on chromosome ten (PTEN), cyclin D1 and P27/Kip1 expression patterns. The results were correlated with clinicopathological parameters. Loss of PTEN protein expression was present in 32.5% of the cases. Cyclin D1 was overexpressed in 54.2% and P27/Kip1 in 89.3% of the cases. Statistically significant associations were found between PTEN and cyclin D1 expression patterns, and cyclin D1 expression and tumour size