Upregulation of miR‐21 expression levels largely attenuated the inhibitory effect of GAS5 on hepatocellular carcinoma cells migration and invasion.19 Study found that in lung cancer patients, low GAS5 expression levels was associated with poor clinicopathological features, and GAS5 might regulate cisplatin resistance via miR‐21 and PTEN.25 A recent study suggested that upregulation of miR‐21 may contribute to the progression of bladder cancer.26 However, it was also shown that some miRNAs could regulate GAS5 expression. This evidence concerns the gene PTEN and lung carcinoma.