Fig. 1From: Traffic lights for retinoids in oncology: molecular markers of retinoid resistance and sensitivity and their use in the management of cancer differentiation therapyPossible mechanisms of retinoid resistance. Cancer cell retinoid resistance may be caused by several independent mechanisms including (1) decreased retinoid uptake; (2) intracellular retinoid metabolism; (3) altered intracellular retinoid availability due to CRAB protein binding; (4) increased retinoid efflux by ABC transporters; (5) increased retinoid catabolism catalyzed by cytochrome P450; (6) decreased RAR and/or RXR expression; (7) inhibited retinoid-induced transcription by the repressor complex, (8) altered coactivator structure, expression, or activity; (9) altered downstream target gene expressionBack to article page