Using both CD44high/CD24low marker profile (Fig. 1H) and ALDHhigh activity (Fig. 1I), we observed that AMPK knockdown reduces the BCSC population in vivo. This parallels our results from the in vitro suspension cultured cells, together suggesting that AMPK contributes to the self-renewal of BCSCs in the tumour microenvironment. This evidence concerns the gene PRKAA2 and neoplasm.