Guerra G, Testa D, Salzano FA, et al. - In the present study, the researchers sought to examine matrix metalloproteinases (MMP-2, MMP-7, and MMP-9) and their tissue inhibitors (TIMP-1 and TIMP-2) concentration in different etiopathogenetical groups of individuals with nasal polyposis (NP) in relation to recurrence after sinonasal surgery. The study group comprised of 45 individuals with NP (those with allergic rhinitis, nonallergic rhinitis and asthma or nonallergic rhinitis, and obstruction of osteomeatal complex [OMC]) who had endonasal sinus surgery. In addition, 10 patients who had septoplasty as control were gathered. In patients with nonallergic rhinitis and asthma, a higher risk of recurrence was observed than in those with allergic rhinitis and nonallergic rhinitis and obstruction of OMC after 36 months of surgery. In this investigation, the pathogenesis of NP related to MMPs and their inhibitors concentrations in polypoid tissue was evaluated.