Analysis of Ki-67 immunoreactivity in recurring and nonrecurring nasal polyps.

Objective: Nasal polyps are common, abnormal lesions. Recurrence of the nasal polyposis is prevalent and a severe problem. The aim of this study was to investigate the relationship between Ki-67 immunoreactivity and the risk of recurrence of nasal polyps. Ki-67 staining of polypectomy material was tested as a risk factor for recurrence independent of etiologic factors or treatment modalities.

Design: Retrospective study.

Setting: University hospital.

Main Outcome Measure: Ki-67 immunoreactivity.

Methods: Pathologic specimens from patients with nonrecurrent and recurrent nasal polyps archived at the Department of Pathology were reviewed, and the most suitable blocks were chosen among the excision materials. Ki-67 antibody staining was investigated immunohistochemically using the avidin-biotin-peroxidase method. The percentages of nuclei immunostained for Ki-67 of at least 1000 epithelial cells in the most intensive staining areas at final magnification (x400) were calculated and defined as the labeling index. The Mann-Whitney U-test was used to compare the Ki-67 labeling index in the nonrecurring and recurring nasal polyp groups.

Results: The mean Ki-67 labeling index was 1.4 +/- 1.972 (range 1-87 in 1000 epithelial cells) in the nonrecurrent nasal polyp group and 17.8 +/- 5.67 (range 82-446 in 1000 epithelial cells) in the recurrent nasal polyp group; the difference between the nonrecurrent and the recurrent group was significant (p < .01).

Conclusion: The results of this study clearly demonstrate that proliferative activity in the surface epithelial cells of recurring nasal polyps is significantly higher than that in nonrecurring nasal polyps.