The level of epidermal growth factor receptors expression is correlated with the advancement of colorectal adenoma: validation of a surface biomarker

INTRODUCTION: Data about the expression of Epidermal Growth Factor Receptors (EGFRs) in colorectal adenomas remain scarce. RESULTS: 101 patients were enrolled including 53 controls. All adenomas (n = 38) and CRC (n = 5) were EGFR positive. Hyperplastic polyps (HP) (n = 8) and control colons (n = 53) were EGFR negative in half of cases (p < 0.0001). A well significant gradient of increased EGFR expression was observed between adjacent mucosa, hyperplastic lesions, low grade dysplasia (LGD) (n = 30), high grade dysplasia (HGD) adenomas (n = 9) and cancers (p < 0.0001). EGFR overexpression was reported in 100% of cancers, 77.8% of HGD, and 10% of LGD adenomas. By multivariate analysis in adenomas, associated factors with EGFR overexpression were HGD and tubulo-villous feature. MATERIALS AND METHODS: All patients undergoing colonoscopy in the university center of Saint-Etienne were eligible to the study from December 2015 to March 2016. In patients with colorectal neoplasia (lesions group), biopsies were performed on the lesion before its resection, and on the adjacent and distal colon mucosa. In control group, biopsies were performed in the right and left side colon. The EGFR expression was assessed by immunohistochemical scores (Goldstein grade, intensity of staining, composite score), using a primary mouse monoclonal antibody (EGFR, clone 113, Novocastra). Outcomes were compared using Kruskal-Wallis and/or Mann-Whitney-U tests, appropriately. The associated clinical, endoscopic and histological factors with EGFR overexpression (composite score ≥ 6) were assessed for adenomas by logistic regression. CONCLUSIONS: EGFR are early involved in colorectal carcinogenesis, and their expression is strongly correlated to the neoplasia stage, leading to validate EGFR as an interesting surface biomarker of adenomas.