Prognostic implication of silver-binding nucleolar organizer regions (AgNORs) in oral squamous cell carcinoma

Silver-binding nucleolar organizer regions (AgNORs) were counted in sections from formalin-fixed, paraffin-embedded tissue blocks of oral squamous cell carcinoma. Thirty-nine cases, that comprised poor prognostic group (n = 19) and good prognostic group (n = 20), were examined with respect to the relation between AgNOR counts and histologic grading, and correlation between AgNOR counts and prognosis. The pooled mean AgNOR counts were: Grade 1 carcinomas, 6.39 +/- 1.67 (mean +/- SD; n = 35); Grade 2, 9.74 +/- 1.72 (n = 3). Mean AgNOR count of Grade 3 was 6.19 +/- 2.37 (n = 1). The pooled mean AgNOR count in poor prognostic group was higher than that in good prognostic group. Five-year survival rate of the cases with high AgNOR counts (greater than or equal to 6.5) was significantly lower than that with low AgNOR counts (less than 6.5). High AgNOR counts are highly suggestive of poor prognosis in oral squamous cell carcinoma.