Quantitative immunoexpression of EGFR in oral potentially malignant disorders: oral leukoplakia and oral submucous fibrosis

Many oral squamous cell carcinomas develop from potentially malignant disorders (PMDs) which include a variety of lesions and conditions characterized by an increased risk for malignant transformation. This study evaluated the quantitative expression of EGFR in normal oral mucosa, oral leukoplakia and oral submucous fibrosis to predict the malignant risk in compliance with the intensity of staining with EGFR. Thirty subjects were included in the study, consisting of 10 oral leukoplakia (OL), 10 oral submucous fibrosis (OSMF) and 10 normal oral mucosa (NOM) as the control group. Owing to the histopathological confirmation of precancerous state of tissue, 4-µm-thick sections of tissue were taken from paraffin-embedded wax blocks for immunohistochemical staining for EGFR. All the control cases showed positive expression for EGFR, while 20% of oral leukoplakia and 40% of OSMF cases showed strong expression (3+), 40% of OL and 30% of OSMF cases showed weak expression (2+), and 40% of OL and 30% of OSMF cases showed poor expression (1+) compared to controls (P=0.012). EGFR expression levels in the premalignant lesion appear to be a sensitive factor in predicting the neoplastic potential. This suggests that EGFR may serve as a biological marker to identify high-risk subgroups and guide prophylactic therapy with chemopreventive drugs or surgical intervention to prevent progression to carcinoma. Hence, further investigations in the direction of chemopreventive trials with a larger sample size are suggested to determine its role in the head and neck tumorigenesis.