In fact, it has been reported that in humancolon cancer cells the combination of the RXR and PPARγagonists produces greater efficacy in growth inhibition than either singleagent alone, and this is associated with a cooperative reduction in the levelsof cyclooxygenase-2 (COX-2) expression and prostaglandin E2 (PGE2)synthesis [58]. The gene discussed is PTGS2; the disease is cancer.