beta-Catenin expression pattern in primary oesophageal squamous cell carcinoma. Relationship with clinicopathologic features and clinical outcome

beta -Catenin has an essential role in intercellular adhesion and signal tr ansduction. beta -catenin functions as a transcriptional activator downstre am in the Wnt signalling pathway. Cytoplasmic stabilisation of beta -cateni n, mainly due to inactivating mutations of the adenomatous polyposis coli ( APC) tumour suppressor gene or activating mutations in exon 3 of the beta - catenin gene, can activate this important pathway in the development of sev eral carcinomas. To determine whether this pathway for malignant transforma tion is important in oesophageal cancer, we analysed 39 primary oesophageal squamous cell carcinomas (OSCC). Immunohistochemical expression of beta -c atenin was studied in formalin-fixed, paraffin-embedded tissue samples. Res ults were correlated with clinicopathological parameters and immunohistoche mical expression of the proteins p53, E-cadherin, bcl-2 and Ki-67. All exam ined OSCC had beta -catenin expression localised in the cellular membrane, frequently with a heterogeneous pattern. Seven (18%) cases also showed immu noexpression in the cytoplasm and nuclei of the tumour cells. These seven t umours were localised in the upper (three) or in the middle third (four) of the oesophagus. Only one patient had p53 expression and all had bcl-2 expr ession. The consensus sequence for glycogen synthase kinase (GSK) 3 beta ph osphorylation in exon 3 of the beta -catenin gene was studied using polymer ase chain reaction and direct sequencing in the seven cases with nuclear be ta -catenin expression. No genetic alteration was suggest that beta -cateni n expression found. These results suggest that beta -catenin expression may characterise a subset of OSCC.