[Developmental carcinogenesis in the cheek pouch of the hamster induced by DMBA using on light microscope]

OBJECTIVE:In this study that the DMBA was applicated to induce the premalignantal changes of the cheek pouches of 89 hamsters in various stage,the result was shown that the slight epithelial displasia was occured 3 weeks later,the medium displasia was occured 5 weeks later,and the severe displasia or the carcinoma in situ was occured 6-9 weeks later.It is suggested that the suitable experimental period of the hamster's carcinogenesis is during 1-3 weeks.