EGFR expression in pancreatic adenocarcinoma. Relationship to tumour morphology and cell adhesion proteins

Aims We aimed to study epidermal growth factor receptor (EGFR) expression in surgically resected pancreatic ductal adenocarcinomas (PDACs) by immunohistochemistry and their relationship to clinicopathological features, cell proliferation and cell adhesion protein expression. Methods A total of 99 PDACs were analysed on tissue microarrays for EGFR, E-cadherin and beta-catenin expression patterns in tumour cells. The percentage of cells expressing the three proteins (membrane, cytoplasm or nuclear pattern) and of Ki67-positive tumour cells was assessed. Tumour protein expression was studied with regard to clinicomorphological features, Ki67 index and for postsurgical survival. Results Membrane tumour EGFR correlated with histological poor differentiation (dedifferentiation), increased number of mitoses and severe tumour cell atypia (pleiomorphism) as well as with aberrant adhesion protein expression such as nuclear beta-catenin and cytoplasmic E-cadherin. Cytoplasmic tumour E-cadherin correlated with an increased Ki67-positive tumour cell component, whereas nuclear E-cadherin correlated with a shorter postsurgical overall survival, as well as with tumour necrosis and an abundant clear cell component. Conclusions In conclusion, the results of our study suggest a complex role for EGFR in PDAC carcinogenesis, tumour expression of this protein being associated with tumour dedifferentiation, mitotic activity or pleiomorphism, as well as with aberrant tumour cell adhesion protein expression.