A comparative study for selectivity of micronuclei in oral exfoliated epithelial cells

BACKGROUND: Micronucleus (MN) represents small, additional nuclei formed by the exclusion of chromosome fragments or whole chromosomes lagging at mitosis. MN rates, therefore, indirectly reflect chromosome breakage or impairment of the mitotic apparatus. During the last few decades, micronuclei (“MNi”) in oral exfoliated epithelial cells are widely used as biomarkers of chromosomal damage, genome instability and cancer risk in humans. However, until now only little attention has been given to the effect of different staining procedures on the results of these MN assays. AIM: To compare the MNi frequencies in oral exfoliated epithelial cells using three different stains, i.e.,Feulgen stain, Papanicolaou stain (Pap) and hemotoxylin and eosin stain (H and E). MATERIALS AND METHODS: Oral exfoliated cells from 45 cases of potentially malignant disorders (15 oral submucous fibrosis, 15 lichen planus and 15 leukoplakia) and 15 controls with healthy mucosa, were taken and MNi frequencies (No. of MNi/1000 cells) were compared using three different stains. RESULTS: Mean MNi frequency in cases was found to be 3.8 with Feulgen stain, 16.8 with PAP and 25.9 with H and E. In controls, mean MNi frequency was 1.6 with Feulgen stain, 7.7 with PAP and 9.6 with H and E stain. Statistically significant value (P < 0.01) were observed when the three stains were compared together using Kruskal Walli's ANOVA test. CONCLUSION: Feulgen being a DNA-specific stain gave the least counts, although statistically significant results from the comparison of MNi frequency between cases and controls were obtained with all the three stains.