HOTAIR target genes are highly tissue-specific. (a) Publicly available ChIP data published by Gupta et al.  was used to select 674 genes gaining increased H3K27 trimethylation at promoters following ectopic expression of HOTAIR in MDA-MB-231 breast cancer cells. These were matched with 784 genes that were downregulated in both UC cell lines after stable ectopic expression of HOTAIR (p < 0.01). (b) Venn diagram for differentially expressed HOTAIR target genes in the esophageal cancer cell line KYSE180  and the two UC cell lines VM-CUB1 and 5637 (p < 0.01) illustrating the minimal overlap of HOTAIR regulated genes between the two cancer types.