IP is a rare tumor of the nasal cavity and paranasal sinuses. Its etiology and factors associated with tumor progression remain unclear. This study aimed to characterize the expression pattern of IPwSCC.

The study included eight subjects with IPwSCC, seventeen subjects with sinonasal IP, and eight normal UT mucosa. Real-time PCR and immunohistochemistry were used to assess the expression and distribution of FoxM1, PLK1, cyclin B1, and cyclin D1 in IP tissues and standard control. The expression of FoxM1, PLK1, cyclin B1, and cyclin D1 in IPwSCC was evaluated using immunohistochemistry.

The mRNA expression of FoxM1, PLK1, cyclin B1, and cyclin D1 was significantly upregulated in IP tissues versus average UT by real-time PCR. The percentage of positive FoxM1-staining cells was statistically higher in IPwSCC than IP and normal UT mucosa. Both mRNA and protein expression of FoxM1 in IP with or without associated squamous cell carcinoma was correlated with tumor histological grades.

The study concluded that FoxM1, a proliferation specific transcription factor, was overexpressed in sinonasal IP and IPwSCC. FoxM1 might be a key molecule associated with the growth of IP and malignant transformation of IP into IPwSCC.

Reference: https://journals.sagepub.com/doi/full/10.1177/1945892419863193