EPITHELIAL-CELL PROLIFERATION, APOPTOSIS, AND APOPTOSIS INHIBITION ININVERTED PAPILLOMAS

Inverted papillomas (IPs) are rare benign tumors of nasal epithelium w ith high recurrence rates and malignant transformation potential, Thei r etiology is still uncertain, and the mechanism of their growth has n ot yet been fully described, The purpose of this study was to detect, quantify and compare cell proliferation, apoptosis, and apoptosis inhi bition in hyperplastic epithelium from IPs and in inflammatory nasal p olyps (NPs), IP samples were obtained after surgical removal of tumor in 13 patients, and NPs were sampled during endoscopic ethmoidectomy i ns 10 patients with nasal polyposis. Cell proliferation and apoptosis inhibition, respectively, were assessed by immunohistochemical identif ication of the proliferating cell nuclear antigen (PCNA) and the oncop rotein Bcl-2. Apoptiosis was evaluated by analyzing the DNA fragmentat ion, Cell proliferation and apoptosis were significantly higher in IPs than in NPs (P = .0002 and P = .043, respectively), while apoptosis i nhibition was significantly lower in IPs than in NPs (P = .001). Conce rning IPs, cell proliferation was significantly higher than apoptosis (P = .0029) and apoptosis inhibition (P = .0015), The increase in epit helial cell proliferation seemed to be greater in IPs with dysplasia t han in IPs without dysplasia. Increased epithelial cell proliferation, but not apoptosis and apoptosis inhibition, seems to be involved in t he development of IP.