Morphometric analysis of AgNORs in nonkeratinizing carcinoma and adjacent normal epithelia in the nasopharynx.

Objective: To evaluate the proliferative activity of different types of nonkeratinizing carcinoma and adjacent normal epithelia in the nasopharynx by the quantitative assessment of argyrophilic nucleolar organizer region (AgNOR) proteins.

Study Design: Silver staining of nucleolar organizer regions (NORs) was applied to 70 paraffin sections of nonkeratinizing carcinoma in nasopharyngeal biopsies. Fifty-four of the 70 cases had differentiated nonkeratinizing carcinoma (DNC), and the remaining 16 had undifferentiated carcinoma (UC). Nineteen of these 70 samples proved to contain, besides carcinoma, normal epithelia (NE), which was used as a control. The epithelial cells and cancer cells were analyzed for their AgNOR features by image cytometric analysis.

Results: As compared with normal epithelia, significant differences were found in mean nuclear area, AgNOR count, mean AgNOR area, AgNOR area ratio and AgNOR area/count ratio between NE and DNC (P < .05) and in mean nuclear area, mean AgNOR area and AgNOR area/count ratio between NE and UC (P < .001). Further, the differences in mean nuclear area, mean AgNOR area and AgNOR area/count ratio were statistically significant between DNC and UC.

Conclusion: The evaluation of AgNORs is a useful histologic assessment of rapidity of cell proliferation in malignant and benign lesions and demonstrated that UC had more rapidly proliferative activity than DNC in this study.