Anaplastic large cell lymphomas and Hodgkin's disease: distinctive growth features and expression of p34cdc2 /cyclin B-1

The clinical aggressiveness of a neoplastic process is largely determined by its growth, which results from cell production minus cell loss. We evaluated the potential of growth- related parameters in the differential diagnosis of Hodgkin's disease (HD), anaplastic large cell lymphoma, common type (ALCL-C), and its Hodgkin's like variant (ALCL-HL). These three conditions share some common properties, e.g. CD30 positivity. Highly significant differences were found between HD and ALCL-C. In particular, CD30+ cells in HD exhibited markedly higher mitotic indices (MI), multinucleation indices (MNI), DNA fragmentation indices (DFI, comparable to apoptotic indices) and percentages of mummified elements (MF), but distinctly lower ana-telophase indices (ATI, index of supposedly successful mitoses) than those in ALCL-C. Interestingly, the percentages of Ki-67 (MIB-1)+ large atypical cells (LAC), often referred to as " growth fractions", did not differ significantly among the three lymphomas types tested. In view of the disturbed mitotic process of CD30 cells in HD, special attention was paid to the two major proteins regulating the G2-M phases of the cell cycle: distinctly lower percentages of LAC expressing cyclin B-l (shortly: cyclin-B) in cytoplasm and nucleus (BCN) were registered in HD than in ALCL-C, while the reverse was true for the presence of p34cdc2 (shortly, p34). As regards the above parameters, ALCL-HL took a somewhat intermediate position between HD an ALCL-C, but was closer to the latter. A stepwise discriminant analysis revealed the following order of discriminant power of the parameters used to differentiate between the lymphomas: BCN > MNI > p34 > ATI > MF > MI. The other parameters tested, including the percentages of Ki 67+ CD30+ cells, were of little or no importance in this respect. Thus, anti-cyclin-B and anti-p34 antibodies may be useful tools in an immunohistochemical distinction of HD and ALCL.