Elevated frequency of micronucleated cells in the buccal mucosa of individuals at high risk for oral cancer: betel quid chewers.

The micronucleus test was applied to buccal mucosa cells of 2 population groups at high risk for oral cancer: Khasis of the northeastern hill region of India, who eat raw betel nuts together with betel leaves and lime, and residents of the state of Orissa (India), who chew betel quids consisting mainly of perfumed tobacco, dried betel nut, betel leaf, lime and several spices. Micronuclei were scored on Feulgen/fast green-stained smear preparations of exfoliated cells obtained by scraping the surface of the buccal mucosa. All 17 raw betel nut eaters and all 20 chewers of betel quids had significantly elevated frequencies of micronucleated mucosa cells over nonchewing controls of comparable ethnic background and dietary habits. The frequencies of micronucleated exfoliated cells were higher at the site within the oral cavity where the quid was kept compared to those at the opposite buccal wall. The micronuclei frequency was lower among individuals chewing a raw betel nut, betel leaf and lime mixture compared to those using tobacco,-betel nut-, lime- and betel leaf-containing quids. Micronuclei frequencies in exfoliated human cells seem to represent a useful 'internal dosimeter' for estimating exposure to genotoxic, and by implication, carcinogenic agents in the tissue from which cancers will develop.