Labelling patterns of carcinomas of the cervix and their precancerous stages after 3H-thymidine incorporation.

1. In-vitro labellings of non-keratinizing squamous cell carcinomas of the cervix uteri yielded greatly differing labelling indices (2.1% to 20.2%) and less greatly varying mitotic indices 0.2% to 1.0%). When the existing limits are taken into account, these values may be indicative of the growth intensity of tumours. 2. The labelling indices obtained for the individual layers of both the normal and atypical squamous epithelium of the portio uteri show that there takes place with the growing degree of dysplasia via the carcinoma in situ to the microinvasive carcinoma a progressive broadening of the zone of growth. Parallel to this, there is an increase in labelling intensity, although it is not possible to derive there from a criterion of malignancy in a given case.