Nasal polyps: p53 over-expression, PCNA index and C-fos activation

IDEA The nasal polyps consist of edematous myxoid stroma infiltrated by inflammatory cells, mainly eosinophils, covered by respiratory epithelium, frequently undergoing hyperplasia and squamous metaplasia. However, the etiology and the pathogenesis of nasal polyps are still limited. The aim of the present work is to describe the biological features of nasal polyps. METHOD We investigated 33 cases of nasal polyps and 11 control cases of normal mucosa. Immunohistochemistry for the study of p53, proliferating cell nuclear antigen (PCNA) and c-fos was applied. RESULTS The evaluation of PCNA index ranged from 0.5 to 18.2%, with a mean value of 6.8%, significantly higher than in normal mucosa (2.9%). Over-expression of the p53 oncoprotein was observed in 16 cases of nasal polyps and was significantly related to a high PCNA-index, as well as to c-fos expression (p<0.05). CONCLUSIONS Our results suggest that p53 over-expression, PCNA index and c-fos expression play a role in the pathogenesis of nasal polyps. We suggest that the immunohistochemistry study of p53, PCNA and c-fos allow to obtain information on the biological features of the nasal polyps, identifying the more aggressive lesions that tend to recur even after accurate surgical removal and that thus require more rigorous follow up.