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Epithelial Cell Proliferation in Nasal Polyps Could Be Up‐Regulated by Platelet‐Derived Growth Factor

The modifications of epithelial differentiation and proliferation observed in nasal polyps (NP) could be related to local secretion of growth factors, among which platelet‐derived growth factor (PDGF) could play a key role. We therefore prospectively studied, by immunohistochemistry, proliferating cell nuclear antigen (PCNA, an S‐phase cell marker), PDGF, and CD‐68 (activated macrophages marker) expression in NP and inferior turbinate mucosa (NM) in 11 patients. Our data show that PCNA and PDGF expression are increased in NP epithelium, while CD‐68 expression is increased in NP epithelium and lamina propria when compared to NM. Increased local PDGF secretion by numerous activated macrophages could therefore be involved in epithelial cell proliferation up‐regulation in NP. PDGF could also be involved in the pathogenesis of NP via its connective tissue remodeling actions.