LOW VERSUS HIGH CELL TURNOVER IN DIFFUSELY GROWING NON-HODGKINS-LYMPHOMAS

Cell loss, perhaps as important as cell production in determining the size of an expanding cell population, has not usually been registered in quantitative cellular kinetic analyses of neoplastic disorders. The present retrospective study on various types and subtypes of non-Hodg kin's lymphomas (NHLs; n = 170) was designed to test the usefulness of a novel additional parameter, the 'turnover index' (TI), which is the sum per case of the mitotic index and the apoptotic index. Results do cument that TIs clearly distinguished between categories and subtypes of NHLs according to the Kiel classification. Cluster analysis of TIs plotted against the percentage of Ki-67-positive cells per case reveal ed that about one-third of the high-grade malignancy lymphomas actuall y belonged to the low-turnover lymphomas. Overall survival was longer in the low- than in the high-turnover group of lymphomas. Assessment o f TIs can, for practical diagnostic purposes, be replaced by counting mitotic figures and apoptotic cells in several high-power fields. The TI concept may help to interpret the kinetics of NHLs in terms of accu mulation vs. proliferation of cells.