Cigarette smoking induces overexpression of c-Met receptor in microvessels of oral lichen planus

INTRODUCTION Cigarette smoking is related to many pathological conditions; however, chemical substances affect the oral cavity first, so it is important to consider its influence on oral mucosa and oral potentially pre-malignant lesions. The aim of this study was to investigate the effect of smoking on microvessel density in oral lichen planus. Special emphasis was placed on examining the relationship between the expression of c-Met receptor in blood vessels and smoking habits. MATERIAL AND METHODS This study included 34 patients with oral lichen planus diagnosed clinically and verified by histopathological examination and 12 healthy individuals as controls. Biopsy of oral mucosa was performed and specimens were examined for immunohistochemical CD34 and c-Met receptor expression. The microvessel density was established by evaluation of the five most vascular areas within a section. RESULTS Compared to normal oral mucosa, in lichen planus patients, significantly higher blood vessel density and c-Met expression were noted. Irregular distribution of microvessels was typical for oral lichen planus. Also, microvessel density was higher in cigarette smoking patients' tissues than in non-smoker specimens. Furthermore, the association of c-Met expression with smoking habit was statistically significant. CONCLUSIONS Cigarette smoking habit has a direct impact on the oral lichen planus course; therefore, close follow-up of these patients is mandatory.