Relationship between intraepithelial neoplasia of the cervix and the size and number of nucleolar organizer regions.

A silver colloid technique was applied to 18 colposcopic biopsies of the cervix. These comprised 7 cases of cervical intraepithelial neoplasia I (CIN I), 5 cases of CIN II, and 6 cases of CIN III. The nucleolar organizer regions subsequently visualized (AgNORs) were enumerated using an oil immersion lens. The maximum diameters of the AgNORs and aggregates thereof were measured, by hand, from carefully calibrated monochrome photographs. The mean numbers of AgNORs subsequently identified steadily increased, whereas the mean sizes of AgNORs decreased from CIN I to CIN III. In CIN I the mean AgNOR number was 2.3 (range 1.8-3.4) and the AgNOR mean maximum diameter (Dmax) was 1.28 microns (range 0.75-1.75). In CIN II the mean number was 3.5 (range 3.1-4.6) and the AgNOR Dmax was 0.98 micron (range 0.9-1.18). In CIN III the mean number was 4.7 (range 4.0-6.1) and the Dmax was 0.62 micron (range 0.51-0.9). CIN III could be distinguished from CIN I and CIN II on the basis of AgNOR sizes, and an inverse relationship between AgNOR numbers and sizes was established.