XIST and breast cancer: Multitudes of researchers have gradually realized how closely lncRNAs, including oncogenic lncRNA HOTAIR [40], lncRNA MALAT1 [41], lncRNA LSINCT5 [42], lncRNA H19 [43] and lncRNA BC200 [44], as well as protective lncRNA XIST [45] and lncRNA GAS5 [46], were intertwined with BC onset and deterioration.