IN-SITU APOPTOTIC AND PROLIFERATION INDEX IN LARYNGEAL SQUAMOUS-CELL CARCINOMAS

The rate of cellular growth is mainly influenced by the balance betwee n cell proliferation and cellular decay. Since to our knowledge, no st udy so far has analysed the rate of proliferation and apoptosis in the normal laryngeal mucosa and in invasive laryngeal carcinomas, we perf ormed a morphological analysis on both parameters in biopsies from 30 patients with laryngeal carcinoma. We applied the TUNEL end labelling technique for the investigation of apoptosis and immunohistochemistry (Ki-67 antigen) for the determination of the cell proliferation. In ou r study we demonstrated that invasive tumour growth of the larynx coin cides with an increase of both cellular proliferation and apoptosis. B oth parameters, however, affected various tumour areas differently. Wh ile there was a preferential expression of the Ki-67 antigen at the tu mour-stroma interface, apoptotic figures could be found randomly distr ibuted in the tumour. This indicates that the replication of tumour ce lls and tumour cell decay are differently distributed and possibly ind ependently regulated. Since we observed a particularly strong increase of cell proliferation at the tumour-stroma interface which outnumbere d the corresponding rate of apoptosis by far, the enhanced cell prolif eration at the tumour border seems to be a main factor for tumour grow th. A statistical evaluation revealed significant correlation between the apoptotic index and the degree of tumour cell differentiation, ind icating that a high rate of apoptosis coincides with a high level of t umour cell differentiation. There was, however, no statistically signi ficant correlation between prognostic clinical parameters and the rate of apoptosis or that of proliferation.