Overexpression of Hepatocyte Growth Factor and Its Receptor c-Met in Nasal Polyps

OBJECTIVES: To investigate the expression and distribution of hepatocyte growth factor (HGF) and c-Met proteins in normal nasal mucosa and in nasal polyps and to evaluate the possible effects of HGF and c-Met on the development of nasal polyps. DESIGN: Prospective study. SETTING: Tertiary academic institution. PATIENTS: Normal inferior turbinate mucosa was obtained from 20 patients undergoing surgery for augmentation rhinoplasty. Nasal polyps were obtained from 20 patients undergoing endoscopic sinus surgery for chronic polypoid sinusitis. INTERVENTIONS: Semiquantitative reverse-transcriptase polymerase chain reaction, immunohistochemistry, and Western blot analysis were performed. MAIN OUTCOME MEASURES: The expression and distribution of HGF and c-Met were analyzed. RESULTS: Using immunohistochemistry, moderate to high levels of HGF were mainly localized in submucosal glands of nasal polyps, while c-Met was detected in submucosal glands and in epithelial cells. In normal turbinate mucosa, immunopositive HGF was detected in submucosal glands, where faint staining was found, while c-Met was noted in epithelial cells and in submucosal glands. Semiquantitative reverse-transcriptase polymerase chain reaction and Western blot analysis showed that HGF expression was increased in nasal polyps compared with that in normal turbinate mucosa. The same result was observed for c-Met. CONCLUSION: Elevated c-Met expression in combination with expression of HGF in nasal polyps may enhance the proliferation of epithelial cells and submucosal glandular cells through the release of HGF, which activates c-Met receptors in nasal polyps.