HOTAIR and breast cancer: For instance, the widely studied lncRNAs, including MALAT1, H19 and HOTAIR, have been reported to promote tumour aggressiveness.12, 13, 14, 15 The expression of lncRNA HOTAIR in epithelial cancer cells increased breast cancer invasiveness and metastasis via enforcing the expression of polycomb repressive complex 214; and MALAT1 expression promotes the aggressiveness of renal cell carcinoma (RCC).12 These data suggested the important roles of lncRNAs in tumorigenesis and development.