A synthetic retinoic acid agent with potential antineoplastic, chemopreventive, teratogenic and embryotoxic properties. Bexarotene selectively binds to and activates retinoid X receptors (RXRs), thereby inducing changes in gene expression that lead to cell differentiation, decreased cell proliferation, apoptosis of some cancer cell types, and tumor regression. OR A type of smokeless tobacco that is made in India and is widely used throughout Asia. It is a mixture of tobacco, crushed areca nut (also called betel nut), spices, and other ingredients. It is used like chewing tobacco and is placed in the mouth, usually between the gum and cheek. Betel quid with tobacco contains nicotine and many harmful, cancer-causing chemicals. Using it can lead to nicotine addiction and can cause cancers of the lip, mouth, tongue, throat, and esophagus. Also called gutka.