The co-ordination of HOTAIR and PRC2 down-regulates miR-34a expression and activates miR34a target genes, such C-Met (HGF/C-Met/Snail pathway) and Snail, which are central players in the epithelial-mesenchymal transition (EMT) in advanced stages of gastric cancer. This evidence concerns the gene SNAI1 and gastric cancer.