Morphometric analysis of AgNORs in imprints and sections from non-Hodgkin's lymphomas. An approach to standardization.

The argyrophilic nucleolar organizer region (AgNOR) technique was applied to tissue sections and touch imprints from 20 non-Hodgkin's lymphomas (NHL). The mean nuclear area (NA), mean AgNOR area/nucleus (AA) and NOR percentage nuclear area (NPNA) were determined using image analysis. The AgNOR count, NA and AA were significantly higher in touch imprints than tissue sections within tumors of the same histologic grade. However, no significant difference was observed for NPNA between imprints and sections within tumors of the same grade. Both the mean AgNOR number and the NPNA were significantly higher in aggressive NHL (n = 10) than indolent NHL (n = 10), regardless of sampling method. It is suggested that the NPNA is invariant to the sampling technique; NPNA values from touch imprints and tissue sections can be compared directly. Furthermore, because NPNA is calculated independent of AgNOR number, it is less subjective than manual counting.