Topographic gene expression in the sinonasal cavity of patients with chronic sinusitis with polyps.

OBJECTIVE To determine whether variations in gene expression exist at multiple subsites along the sinonasal tract in patients with chronic sinusitis with polyps and in healthy controls. STUDY DESIGN Prospective, controlled study. SETTING Academic medical center. SUBJECTS AND METHODS Tissue expression levels of 5 genes, previously found to be characteristic of ethmoid polyps, were measured using real-time quantitative polymerase chain reaction in 100 sinonasal tissue samples. Specimens harvested from 5 regions--the ethmoid sinus, septum, inferior turbinate, middle turbinate, and lateral nasal wall--in 10 patients with chronic sinusitis and ethmoid polyps were compared to tissue from similar regions in 10 control patients without sinusitis. Western blot analysis was performed to validate differential gene expression at the protein level. RESULTS Gene expression levels of ethmoid polyps differed significantly from those of healthy ethmoid mucosa, as well as tissue from 4 surrounding anatomical sites in both patients with chronic sinusitis and controls. Alterations specific to the polyp tissue included downregulated genes, prolactin-induced protein (fold change 377.2 ± 169.0, P < .0001), and zinc α2-glycoprotein (fold change 72.1 ± 26.5, P < .0001), as well as upregulated genes, met proto-oncogene (fold change 2.5 ± 0.7, P = .029), and periostin (fold change 7.5 ± 3.4, P = .003). No significant differences in gene expression was found for neurabin 2 (fold change 1.0, P = .99). CONCLUSION The transcriptional pattern of ethmoid polyps appears to be unique compared with other subsites in the sinonasal cavity of patients with chronic sinusitis. Care must be taken when collecting specimens for molecular studies of the sinonasal tract to differentiate polyp from nonpolyp tissue in chronic sinusitis.