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.