Overexpression of tRXRα but not RXRα in MCF-7 breast cancer cells enhanced AKT activation in vitro (Supplementary Fig. 8b) and promoted the growth of MCF-7 tumour in animals, which was suppressed when animal were treated with K-80003 (Fig. 6c; Supplementary Fig. 8c). This evidence concerns the gene RXRA and breast carcinoma.