AgNOR cut-point to distinguish mild and moderate epithelial dysplasia
Article first published online: 19 JUL 2007
Journal of Oral Pathology & Medicine
Volume 37, Issue 2, pages 78–82, February 2008
How to Cite
Chattopadhyay, A. and Ray, J. G. (2008), AgNOR cut-point to distinguish mild and moderate epithelial dysplasia. Journal of Oral Pathology & Medicine, 37: 78–82. doi: 10.1111/j.1600-0714.2007.00585.x
- Issue published online: 19 JUL 2007
- Article first published online: 19 JUL 2007
- Accepted for publication May 30, 2007
- epithelial dysplasia;
Background: Distinguishing mild and moderate epithelial dysplasia is difficult and controversial. We demonstrated earlier that silver-stainable nucleolar organizer region (AgNOR) is a simple, inexpensive and quantifiable method which can standardize this distinction reliably.
Objective: To establish a cut-point mean AgNOR count for epithelial dysplasia validated by bootstrapping.
Methods: One hundred oral leukoplakia biopsies at Dr R. Ahmed Dental College, Kolkata, India, examined for epithelial dysplasia using standard method (gold standard) were assessed for their mean AgNOR counts. A cut-point was selected employing receiver operating characteristic (ROC) curve. This estimate was stabilized by 10 000 resamples (with replacement) using parametric and non-parametric bootstrap, a Monte Carlo statistical method, corrected for bias to estimate standard errors (SE) of cut-point.
Results: Area under the curve (AUC) was 74%; non-parametric method suggested mean AgNOR cut-point = 2.42 AgNORs/nucleus; parametric method suggested cut-point = 2.57. The cut-point 95% confidence intervals (CIs) (bias corrected and accelerated) from parametric method (2.31; 2.66) was lower than non-parametric (2.43; 2.82).
Conclusion: Applying a conservative paradigm, taking the lowest of all bootstrap 95% CIs, we suggest that mean AgNOR count of 2.3 be used as a cut-point for distinguishing between mild and moderate dysplasia. This strategy will provide an inexpensive, meaningful, definitive, reproducible and consistent diagnostic test for epithelial dysplasia.