Clinicopathologic significance of EGFR and Her-2/neu in colorectal adenocarcinomas

The purpose of this study was to determine the prognostic impact of epidermal growth factor receptor (EGFR) and Her2/neu protein expression in colorectal cancer.

Immunohistochemistry was performed in paraffin-embedded specimens of 106 colorectal carcinomas for the assessment of EGFR and Her-2 expression. The results were correlated with traditional clinicopathologic parameters and patient outcome.

Membranous expression of EGFR was found in 50 cases (47.16%) and cytoplasmic expression in 32 cases (30.19%). Membranous overexpression of Her-2 was identified in six cases (5.66%) whereas cytoplasmic expression was found in 18 cases (16.98%). The correlation with other clinicopathologic parameters demonstrated a statistically significant expression of membranous EGFR in the older age group and a statistically significant expression of membranous Her-2 in patients with negative lymph nodes. None of the other parameters or patient prognosis was associated with EGFR or Her-2 membranous expression. Cytoplasmic expression was not related with any of aforementioned parameters.

Conventional immunohistochemistry was unable to reveal any association between EGFR expression and outcome predicted by the biologic role of EGFR in tumor behavior. Her-2/neu is not a pivotal pathway in colorectal cancer progression because it seems to be expressed in early stages of colorectal cancer.