INAPPROPRIATE RETINOIC ACID RECEPTOR-BETA EXPRESSION IN ORAL DYSPLASIAS - CORRELATION WITH ACQUISITION OF THE IMMORTAL PHENOTYPE

Retinoids are useful in the treatment of premalignant oral lesions and in preventing the occurrence of second primary cancers after resectio n of the initial primary oral cancer, but long-term prognosis is still poor, presumably due to malignant cells escaping retinoid control, Pr evious work has shown that loss of expression of retinoic acid recepto r beta is one of the most consistent molecular changes during oral can cer progression in vivo, In this report we demonstrate, using a novel panel of primary cultures of oral lesions, that loss of retinoic acid receptor beta expression at the dysplasia stage occurs during the tran sition from senescent to immortal phenotype but may occur independentl y to the loss of CDKN2A/p16 expression.