Proliferation kinetics of malignant non-Hodgkin's lymphomas related to histopathology of lymph node biopsies.

Since lymphomas of high and low malignancy have been differentiated by the Kiel-classification, the cell kinetics of malignant lymphomas have become an interesting subject. In 20 non-Hodgkin's lymphomas we have determined the initial labelling index, the mitosis index, the proliferation rate and the durations of DNA-synthesis and mitosis. The kinetic variables have been estimated by using an in vitro-incubation of fresh biopsies and double-labelling with radioactive DNA-precursors. in 8 lymphomas of low malignancy we found an initial labelling index of 7.8%, a mitosis index of 0.3% and a potential tumour doubling time of 100.2 h for a cell production rate without regard to cell loss. On the other hand, lymphomas of high malignancy showed a labelling index of 16.7%, a mitosis index of 0.7% and a potential tumour doubling time of 40.5 h. All these values could be differentiated with high statistical confidence. DNA-synthesis time and mitosis time of both lymphoma groups did not show any significant differences. From these findings we obtained confirmation of the cyto-morphological principles used in classifying lymphomas.