The influence of pre-operative radiotherapy on the expression of p53 and adhesion molecules: correlation with treatment results in patients with squamous cell carcinoma or adenocarcinoma.

Abstract

E-cadherin and the catenins are responsible for inter-cellular adhesion in epithelial tissues. E-cadherin and/or catenin expression is often altered in malignancies, leading to increased invasiveness and metastatic activity of tumour cells. Intact adhesion molecules reduce the risk on distant metastases. This is confirmed by studies mostly performed on surgical series, correlating e-cadherin expression in tumours with prognosis and treatment outcome. It has become more apparent that anti-cancer treatment by itself can also affect the expression of adhesion molecules. We therefore suggest that the prognostic value of e-cadherin expression may depend on the treatment modality and the sequence of therapies administered for malignant tumours. We used paraffin embedded specimens from patients with rectal tumours and patients with laryngeal tumours treated by short course radiotherapy before definitive surgery. Expression of p53, e-cadherin, and beta-catenin was determined in pre-radiotherapy biopsies and in the surgical specimens. Material was available from 37 patients. We found no correlation between the expression of p53, e-cadherin or beta-catenin and pre-treatment parameters. Mutated p53 in pre-radiation biopsy correlated with increased occurrence of distant metastases and there was an unexpected trend for abnormal e-cadherin expression to correlate with reduced metastases. The prognostic value of p53 no longer existed after examination of the surgical specimens (post-radiotherapy). There was a trend for e-cadherin to reverse from abnormal to normal expression in laryngeal squamous cell carcinomas after radiotherapy, in 5/7 cases it was accompanied with p53 conversion from positive to negative expression. Based on this study it is suggested that the predictive value of the e-cadherin expression for the occurrence of distant metastases in tumours treated by radiotherapy before surgery may be different from that found in tumours treated by surgery only. This may be related to the influence of radiotherapy on e-cadherin expression, especially in squamous cell carcinomas. Alteration in p53 expression was of predictive value only in pre-treatment biopsies and the beta-catenin status did not correlate with treatment outcome in this series.