The proliferating activity of
leukoplakia and
squamous cell carcinoma (SCC) was estimated using
proliferating cell nuclear antigen (
PCNA) immunostaining and
silver-binding argyrophilic nucleolar organizer region (AgNOR) staining. Twenty-eight
leukoplakias and 15 SCCs of the oral cavity were used in this study. The mean+/-S.D. of
PCNA LI and AgNOR counts were 7.7+/-6.0% and 2.43+/-0.68/nucleus in
leukoplakias, and 22.3+/-11.6% and 4.77+/-1.49/nucleus in SCCs. Both of
PCNA LI and AgNOR counts were significantly higher in SCCs than in
leukoplakias. There was a significant linear correlation between
PCNA LI and AgNOR counts (p=0.0022) in
leukoplakias, but not in SCCs. In the series of
leukoplakias,
PCNA LI apparently increased in
leukoplakias with dysplasia and malignant transformed cases. Our data suggest that
PCNA LI and AgNOR counts are useful markers of proliferating activity, and
PCNA LI might be a prognostic factor of
leukoplakias.