The elevated expression of osteopontin and vascular endothelial growth factor in sinonasal inverted papilloma and its relationship with clinical severity.

BACKGROUND: Osteopontin (OPN) is involved in cell survival, immunity, and tumor progression. The overexpression of OPN has been proposed as a biomarker of progression and metastasis for several tumor types, but it is still unclear whether it is up-regulated in sinonasal inverted papilloma (SIP). METHODS: We enrolled 33 subjects with SIP and 15 normal controls to determine the importance of OPN and vascular endothelial growth factor (VEGF) in SIP. Using immunohistochemistry, quantitative polymerase chain reaction, and enzyme-linked immunosorbent assay, we examined the distribution, mRNA expression, and protein levels, respectively, of OPN and VEGF. We then correlated these values with clinical severity. RESULTS: The immunostaining levels for OPN and VEGF were significantly increased in SIP tissues compared with control tissues (p < 0.05), as were their mRNA expression and protein levels (p < 0.05). The correlation between OPN and VEGF expression and the clinical stage of SIP was significant (p < 0.05). CONCLUSION: Our findings indicate that OPN and VEGF were both overexpressed in the analyzed SIP tissues and were associated with clinical severity, suggesting that the OPN-VEGF axis might contribute to tumor progression by enhancing angiogenesis. Therefore, OPN may serve as a potential therapeutic target for preventing SIP progression and recurrence.