Other proteins that can bind to Nrf2 and affect its function and expression of its downstream genes include retinoid X receptor alpha (RXRα), which is involved in differentiation and developmental processes [28], and small musculoaponeurotic fibrosarcoma (sMafs), which is involved in the expression of antioxidant- and phase-II-detoxifying enzymes [29]. This evidence concerns the gene RXRA and fibrosarcoma.