Sequential demonstration of nucleolar organizer regions and Ki67 immunolabelling in non-Hodgkin's lymphomas

In order to investigate the relationship between the numbers of interphase silver-stained nucleolar organizer regions (AgNORs) and cell proliferation, we have studied prospectively a small series of non-Hodgkin's lymphomas (NHL). We applied the recently described double staining technique for sequential immunostaining and the AgNOR reaction to the same sections of tumour from each case. The immunostaining was performed with the antibody Ki67, known to demonstrate the nuclei of proliferating cells. A significant difference was found between the AgNOR scores in Ki67+ and Ki67- cells, the counts being much higher in the former than the latter. This was the case for both high- and low-grade NHL and is further evidence that interphase AgNOR counts reflect cell proliferation level, at least in lymphomas.