Silver-binding nucleolar organizer region proteins as a possible prognostic indicator in oral submucous fibrosis

Silver-binding nucleolar organizer region proteins (AgNORs) were counted in sections from formalin-fixed, paraffin-embedded tissue blocks of oral submucous fibrosis (OSMF) and oral squamous cell carcinoma (SCC). Moderately advanced and advanced cases OSMF, and well-differentiated and poorly differentiated cases of SCC, were studied with respect to the relation between AgNOR counts and histologic grading. Normal oral mucosa collected from age- and sex-matched subjects constituted the control group. The pooled mean (+/- SD) AgNOR counts were as follows: normal mucosa, 2.50 +/- 0.52 (n = 5); moderately advanced OSMF, 5.24 +/- 1.23 (n = 10); advanced OSMF, 7.26 +/- 1.12 (n = 10); well-differentiated SCC, 8.29 +/- 1.47 (n = 5); and poorly differentiated SCC, 9.49 +/- 0.74 (n = 5). The pooled mean AgNOR counts in advanced OSMF were higher than in moderately advanced cases (t = 3.84; p < 0.005) and those in poorly differentiated SCC were higher than those of well-differentiated SCC, although the comparison was not significant in the latter (t = 1.63, p > 0.10). AgNOR counts could hold promise for predicting the biologic behavior of OSMF because this study demonstrated a correlation with clinical and histologic grading.