PTEN and hepatocellular carcinoma: For example, lncRNA XIST regulates PTEN expression by sponging miR-181a and promotes hepatocellular carcinoma progression;18 in another study, it was found that lncRNA XIST could promote pancreatic cancer proliferation through miR-133a/EGFR.19 However, other studies indicated that loss of lncRNA XIST is essential for some malignancies.