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Epidermal growth factor receptors play an important role in airway epithelial cell growth and differentiation. The current study investigates the expression profiles of EGF, EGFR and ERBB4 in patients with nasal polyps (NP), and their response to glucocorticosteroid (GC) treatment. Fifty patients with NP (40 without GC treatment and 10 with oral GC) and 20 control subjects with septal deviation were recruited into the study. Protein levels of EGF, EGFR, and ERBB4 were evaluated by immune-staining. In healthy nasal epithelium, EGF and EGFR localized within p63+ basal cells, while ERBB4 localized within ciliated cells. GC-naïve NP epithelium showed weak expression of EGF in 90% of samples versus 5% of controls. EGFR was significantly increased in the epithelium with basal cell hyperplasia from GC-naïve NPs (78%, 31/40) compared to controls (23%, 4/17). EGFR was also found in some degranulating goblet cells. ERBB4 expression was significantly higher in hyperplastic epithelium from GC-naïve NPs (65%, 26/40) than in controls (6%, 1/17). GC treatment restored the EGF expression and normalized the EGFR and ERBB4 expression in NPs. Differential expression patterns of EGF, EGFR, and ERBB4 are essential in epithelial restitution and remodeling in nasal epithelium. [ABSTRACT FROM AUTHOR]

Rationale and Objective: Sirtuin 1 (SIRT1) plays an important role in tumorigenesis and is increased in many human tumors. DBC1 is a negative regulator of SIRT1 via promotion of p53-mediated apoptosis. It is necessary to investigate the expression of SIRT1 and DBC1 in laryngeal and hypopharyngeal squamous cell carcinomas (LSCC and HSCC) and its correlation with available clinical parameters. Methods: The mRNA levels of SIRT1 and DBC1 were measured in 54 paired LSCC or HSCC tumors and corresponding adjacent noncancerous mucosae using quantitative RT-PCR (qRT-PCR). The protein levels of SIRT1 and DBC1 were also evaluated in 120 cases of patients with LSCC or HSCC using immunohistochemical staining. The correlation between SIRT1 and DBC1 expression and clinical parameters was analyzed with Pearson chi-square test. Results: qRT-PCR assay showed that, compared with the paired adjacent noncancerous mucosae, SIRT1 mRNA was significantly decreased in tumors. The immunohistochemical results indicated that the SIRT1 protein was also downregulated in tumors compared with noncancerous mucosae. Moreover, decreased SIRT1 was significantly correlated with the tumor clinical stage and lymph node metastasis. Additionally, DBC1 mRNA was significantly increased in tumors compared with noncancerous mucosae. The immunohistochemical results indicated that the DBC1 protein was downregulated in tumors, which is inconsistent with the results obtained by qRT-PCR. Finally, decreased DBC1 protein was significantly correlated with tumor differentiation, lymph node metastasis, and p53 expression. Conclusions: SIRT1 and DBC1 might be involved in the pathophysiology of laryngeal and hypopharyngeal squamous cell carcinomas and are associated with lymph node metastasis and p53 positive staining in LSCCs and HSCCs. [ABSTRACT FROM AUTHOR]