Aims: Receptor tyrosine kinases epidermal growth factor receptor (EGFR) and HER-2 and cyclooxygenase-2 (COX-2) are promising molecular targets for cancer therapy and/or prevention. The aim was to evaluate EGFR, HER-2 and COX-2 mRNA and protein expression in colorectal cancer patients.
Methods and results: EGFR, HER-2 and COX-2 protein levels were evaluated by immunohistochemistry in malignant tissue, dysplastic tissue and normal mucosa samples from 124 cases with primary colorectal carcinoma. Moreover, the corresponding mRNA levels were assessed by quantitative reverse transcriptase-polymerase chain reaction in 46 colorectal carcinomas. There was strong correlation between mRNA and protein expression for EGFR (P < 0.001), HER-2 (P < 0.004) and COX-2 (P < 0.007). EGFR levels did not correlate with stage of the disease or tumour differentiation. HER-2 and COX-2 levels increased in advanced stages and in differentiated carcinomas. Furthermore, a correlation between HER-2 and COX-2 expression was revealed in neoplastic tissue.
Conclusions: EGFR as well as HER-2 and COX-2 overexpression represent important alterations that are related to the molecular pathways underpinning colorectal carcinogenesis. Further investigation is required to evaluate the impact of these markers on the management of patients with colorectal cancer.