HOTAIR and breast cancer: Transcriptome analysis of 42 BC cell lines revealed 2874 differentially expressed genes in BC malignant cell lines; among these genes, 585 mRNAs, 199 lncRNAs, and 45 transcripts with other functions (such as pseudogenes and snoRNAs) were downregulated, and 1546 mRNAs and 499 lncRNAs, including the lncRNA HOTAIR, the BC-specific lncRNA LINC01016 [39], AL157387.1, the luminal subtype-related lncRNAs DSCAM-AS1 [30], and GATA3-AS1 [27] were upregulated (Figure 2A).