A naturally-occurring acid of retinol. Vitamin A acid binds to and activates retinoic acid receptors (RARs), thereby inducing changes in gene expression that lead to cell differentiation, decreased cell proliferation, and inhibition of carcinogenesis. This agent also inhibits telomerase, resulting in telomere shortening and eventual apoptosis of some cancer cell types. The oral form of vitamin A acid has teratogenic and embryotoxic properties.(NCI04)
