MALAT1 and hepatocellular carcinoma: SNAI1, a key transcription factor in the epithelial–mesenchymal transition, is also a direct target of miR-22, which could be absorbed by MALAT1, promoting the enrichment of enhancer of zeste homolog 2 (EZH2) to inhibit miR-22 transcription, thereby upregulating SNAI1 expression and facilitating HCC invasion and distant metastasis.