The kinetics of cell proliferation in neuroblastomas

The proliferation kinetics of 11histologically undifferentiated neuroblastomas were studied with an autoradiographic in vitro method (labelling with 3H-thymidine and double labelling with 3H- and 14C-thymidine). The cytokinetic parameters revealed a marked individual pattern: LI between 3.0 and 27.8%, Ts 7.2 to 17.8 hr, Tc 13.1 to 266.3 hr, Tm 0.6 to 5.1 hr, T(G1 + G2) 4.3 to 247.6 hr. The potential tumour doubling time (without cell loss) ranges from 20.4 to 415.4 hr. The growth fraction is between 0.48 and 0.58. Cytokinetic investigations of human tumours are extraordinarily important. They cannot only characterize the growth behaviour of malignant tumours, but also provide the basis for an individual therapy. The close correlation between proliferation kinetics and tumour therapy are discussed. These relations may also be summarized in a "cytokinetic therapy index", which allows the general prediction of chemosensitivity. This index is in the field of good or sufficient sensitivity in 9 neuroblastomas; in 2 cases the response to cytostatic agents is questionable from the view-point of cytokinetics.