FLOW CYTOMETRIC ANALYSIS OF CELL-CYCLE FRACTIONS IN ORAL LEUKOPLAKIA

Flow cytometric analysis of cell cycle fractions and DNA ploidy was pe rformed on 39 biopsy specimens of oral leukoplakia. The aneuploidy rat e of these leukoplakias was 9/39 (23.1%) and the mean DNA index of the aneuploid lesions was 1.34. The aneuploidy rate was significantly hig her in severely dysplastic lesions (8/17) than in mildly dysplastic (1 /15, P<0.02) and nondysplastic (0/7, P<0.05) lesions. No significant d ifferences in the percentages of each cell cycle fraction were seen be tween the diploid and the aneuploid leukoplakias. However, the S-phase fraction of the severely dysplastic lesions (23.0%) among the diploid leukoplakias was higher than those of the mildly dysplastic (12.4%) a nd nondysplastic (15.5%) lesions, and the difference between the sever ely dysplastic and the mildly dysplastic lesions was statistically sig nificant (P<0.001). These results suggest that flow cytometric analysi s of cell cycle fractions and DNA ploidy might offer additional inform ation for assessing the malignant potential of oral leukoplakias.