Wang F, et al. - In this investigation, researchers identified the expression pattern of speckled protein 100 (Sp100) in the malignant transformation (MT) of sinonasal inverted papilloma (SNIP) [benign epithelial tumor occurring in the adult nasal cavity and paranasal sinuses, usually in the fifth decade of life] and its association with human papillomavirus (HPV)-16 and HPV-18 infections and other clinical features. This would also help to understand the potential mechanisms for SNIP development. Between September 2009 and August 2016, a total of 40 individual nasal mucosa specimens (25 males and 15 females, age: 26-72 years, mean age: 51.17 years) were obtained from patients treated in the hospital. Investigators found that a positive HPV infection rate is high in the SNIP with MT and correlates with the expression of Sp100. Furthermore, the expression of Sp100 in SNIP with MT is down-regulated, and Sp100 can play a role in SNIP progression.