Real time PCR analyses of expression of E-cadherin, alpha-, beta- and gamma-catenin in human breast cancer for predicting clinical outcome

Background: The E-cadherin catenin system acts as an invasion suppressor of epithelial malignancies. However, it is debatable whether expression of E-cadherin or catenins is a useful prognostic marker in invasive breast cancer. Methods: We measured the expression of E-cadherin and catenins (alpha-, beta-, gamma-catenin) in human breast carcinomas using real time quantitative polymerase chain reaction (Q-PCR) and investigated whether the expression levels were associated with known tumour variables or patient survival (median follow-up 72.2 months). RNA from frozen sections of breast tissue (tumour n = 124, background normal tissue n = 33) was reverse transcribed, quantified and analysed by Q-PCR with results expressed as number of copies of transcript/50 ng RNA. Results: There was no statistically significant difference in the expression of E-cadherin and catenins (alpha-, beta-, gamma-catenin) in the 33 paired normal background and tumour tissues. The expression of E-cadherin, alpha-, beta-, and gamma-catenin in node positive tumours was similar to node-negative tumours. E-cadherin, alpha-, beta-, and gamma-catenin expression in breast tumours was not related to Nottingham Prognostic Index (NPI). There was no significant difference in the expression of E-cadherin, alpha-, beta-, gamma-catenin between the various TNM stages. None of the molecular markers significantly influenced survival. Lymph node status was the only significant predictor of survival. Conclusion: Using real time quantitative PCR there was no difference in the expression of E-cadherin, alpha-, beta-, gamma-catenin between tumour and normal breast tissue. Furthermore, measurement of expression of these molecules was not of prognostic value in predicting long term outcome of women with breast cancer.