[Several parameters of the kinetics of cellular proliferation in human macroglial tumors]

The thymidine labelling index was studied by autoradiography in 95 human macroglial tumours. In 75 supratentorial tumours the values of the labelling index ranged from 0.05% to 20.10%, while in 20 cerebellar tumours it comprised 0.05% to 1.49%. Macroglial tumours of the large hemispheres could be subdivided with statistical significance into two discrete groups according to their labelling index: the group of slowly growing tumours with the labelling index below 2.5%, and the group of faster growing tumours with the labelling index above 2.5%. Gradual spontaneous malignization of the Group 1 tumours turning into Group 2 tumours is hardly probable. The duration of the DNA synthesis phase in 4 macroglial tumours of the large hemispheres in man varied from 5.7 to 7.5 hours.