Presence of the bcl-2 protein and apoptosis in non-Hodgkin's lymphomas with diffuse growth pattern

In an attempt to further clarify the role of the apoptosis‐counteracting protein bcl‐2, non‐Hodgkin lymphomas (NHL, n = 170) were examined immunohistochemically, across the boundaries of histologic classification, for the presence of this oncoprotein, in comparison with apoptotic indices (AI) and percentages of Ki‐67+ cells (growth fraction). The results of this retrospective study revealed a highly significant inverse relationship (“mirror image”) between the proportion of bcl‐2+ cells and the AI per case. Both these parameters, although variable, clearly distinguished low‐ from high‐grade‐malignancy lymphomas according to the Kiel classification. Cluster analysis detected 2 separate groups of high‐grade NHL, one with rather high AI and low percentages of bcl‐2+ cells, comprising most anaplastic large‐cell lymphomas, the other group with reverse characteristics. We found no correlation between the percentage of bcl‐2+ cells per case and overall survival. © 1995 Wiley‐Liss, Inc. Copyright © 1995 Wiley‐Liss, Inc., A Wiley Company