XIST and breast cancer: For example, MALAT1 is a regulator of alternative splicing in breast cancer (Moran et al., 2012; Qi and Du, 2013; Jiang and Bikle, 2014); HOTAIR is overexpressed in a quarter of breast cancers (Gupta et al., 2010; Hung and Chang, 2010); the role of XIST in X chromosome inactivation is linked to BRCA1 tumors (Vincent-Salomon et al., 2007); MEG3 suppresses breast cancer through AKT (Zhang et al., 2017); GAS5 is downregulated in breast cancer and can induce apoptosis (Mourtada-Maarabouni et al., 2009).