HIGH PREVALENCE OF EXPRESSION OF P53 ONCOPROTEIN IN ORAL CARCINOMAS FROM INDIA ASSOCIATED WITH BETEL AND TOBACCO CHEWING

A recent study reported a low prevalence of p53 expression (11%)in ora l squamous cell carcinomas (SCCs) from South Asia, in contrast to a hi gh prevalence (averaging 52%) in other studies. It was proposed that t he different aetiologies for oral SCCs in the South Asia population, i .e. betel and tobacco chewing in combination with smoking and alcohol consumption as compared to smoking and alcohol consumption alone in ot her populations, may account for the low prevalence of p53 expression. To confirm this hypothesis, we examined p53 expression immunohistoche mically in 23 cases of oral SCC from patients in Southern India. Thirt een of the 23 SCCs (56.5%) demonstrated nuclear p53 staining, The expr ession of p53 was strongly correlated with the number of tobacco-conta ining quids chewed per day (r = 0.8). These data support the hypothesi s that carcinogens derived from tobacco and betel chewing may induce p 53 mutations, which in turn are involved in the development of oral ca ncer.