['This study evaluated the relationship between argyophilic nucleolar organizer regions (AgNORs) and the histologic effects of preoperative chemotherapy or external radiation on oral squamous cell carcinoma.', 'Thirty-three cases of oral squamous cell carcinoma that were treated with chemotherapy (pepleomycin or 5-FU) or 60Co external radiation were studied. Biopsies were done on the tumor sites before therapy and the number of AgNORs per nucleus was recorded. After therapy, the tumors were resected and the therapeutic effects were assessed histologically.', 'The number of AgNORs per nucleus before therapy ranged from 4.7 to 12.45 (mean +/- SD, 8.71 +/- 2.26). As the number of AgNORs per nucleus increased, the histological effects of preoperative therapy were enhanced. It was 5.75 +/- 0.77 in cases with a poor histological effect of preoperative treatment, 8.03 +/- 1.85 in cases with a mild histological effect, 9.09 +/- 1.85 in the moderate histological effect group, and 10.46 +/- 1.56 in the excellent histological effect group.'] Does effects of preoperative radiation and chemotherapy on AgNOR count in oral squamous cell carcinoma?