Correlation between NOR sizes and numbers in non-Hodgkin's lymphomas.

A series of 36 cases of non-Hodgkin's lymphomas (NHL) has been studied by means of the argyrophil (AgNOR) method for nuclear organizer regions (NORs). Morphometric analysis of highly magnified photographic images of light microscope preparations of the AgNORs was performed by means of an interactive image analysis system. It was observed that in the low-grade specimens (where NORs are less frequent than in those of high-grade histology), the AgNOR sites were highly significantly (P less than 0.001) larger than in high-grade NHL. In the low-grade lymphomas, the AgNOR maximum diameter (Dmax) ranged from 0.7 to 1.7 micron 2 (mean 1.11 micron 2) and area ranged from 0.48 to 1.99 micron 2 (mean 1.11 micron 2). In contrast, in the high-grade specimens, Dmax was from 0.33 to 0.51 micron (mean 0.41 micron) and the area ranged from 0.082 to 0.19 micron 2 (mean 0.13 micron 2). Thus, a well-defined inverse relationship was observed between AgNOR numbers and their sizes. There was total separation between low- and high-grade values in this series. This light microscope technique offers some advantages over ultrastructural morphometry of interphase NORs (fibrillar centres).