To investigate the expression of epidermal growth factor receptor (EGFR) messenger RNA (mRNA) in human sinus mucosa and to compare the expression of EGFR and EGF among patients with chronic rhinosinusitis (CRS), patients with CRS and nasal polyposis (CRS/NP), and a healthy control group.
Maxillary sinus ostia mucosa was harvested from patients undergoing endoscopic sinus surgery for CRS or CRS/NP and from patients undergoing surgery for non-CRS pathologic conditions (control group). The samples were analyzed using semiquantitative reverse transcription–polymerase chain reaction to detect mRNA of EGFR. Hematoxylin-eosin staining and immunofluorescent staining were used to localize EGFR and EGF in the sinus mucosa.
Three groups (CRS, CRS/NP, and control), each with 10 subjects, were enrolled in the present study.
Main Outcome Measures
Area ratios of positive cells in the epithelia were compared among the CRS, CRS/NP, and control groups. In addition, eosinophils were counted in the subepithelial connective tissue in the 3 groups.
The level of EGFR mRNAs in the sinus mucosa of the CRS and CRS/NP groups was statistically significantly increased compared with that in the control group (P < .01), and no statistically significant difference was found between the sinus mucosa of the CRS group and that of the CRS/NP group (P < .01). On hematoxylin-eosin staining, hyperplasia and metaplasia of epithelial goblet cells were present in the sinus mucosa of the CRS and CRS/NP groups. Epidermal growth factor receptor was mainly expressed in goblet cells and basal cells and was weakly expressed in ciliated cells, while EGF expression was located in epithelial cells and in some inflammatory cells but not in goblet cells. In the control group, expression of EGFR and EGF was lower compared with that in the CRS and CRS/NP groups. No statistically significant area ratios of positive cells differences in staining of EGFR and EGF were found between the CRS group and the CRS/NP group (P > .05), whereas statistically significant differences were found between the control group and the 2 CRS groups (P < .01). The number of eosinophils was statistically significantly increased in the CRS/NP group compared with that in the CRS group (P < .01).
Up-regulation of the EGFR cascade may have an important role regarding mucus production in the sinus mucosa of patients with CRS and CRS/NP associated with hyperplasia and metaplasia of epithelial goblet cells.