CELLULAR KINETIC AND PHENOTYPIC HETEROGENEITY IN AND AMONG BURKITTS AND BURKITT-LIKE LYMPHOMAS

This study asks whether the known genotypic heterogeneity within and b etween endemic or sporadic Burkitt's lymphomas (eBLs and sBLs, n=10 ea ch), and Burkitt-like lymphomas (BLLs, n-12), is reflected in divergen t cytokinetics and related immunophenotypes. There was strong evidence that eBL and BLL grow markedly faster than sBL, as shown by differenc es in mitotic and apoptotic indices. Furthermore, in BLL, the median p ercentage of neoplastic cells immunoreactive for the bcl-2 protein was much higher than that observed in eBL and sBL. The reverse was true f or the median fraction of cells containing c-myc protein. In eBL and s BL, the median fraction of bcl-6 protein-positive cells reached values above 50 per cent, while cells of 8/12 BLLs did not contain detectabl e amounts of this protein. This observation indicates that in this res pect, eBL and sBL resemble normal germinal centres of lymphatic tissue much more than do BLL. Evidence for infection of neoplastic cells by the Epstein-Barr virus (EBV) was observed in 9/10 cases of eBL and in 3/10 of sBL, but not in BLL. EBV-positive lymphomas were associated wi th distinctly lower apoptotic indices and smaller median percentages o f bcl-6-positive cells than EBV-negative tumours. (C) 1997 by John Wil ey & Sons, Ltd.