LncRNA-GIHCG contributes to histone H3K27 trimethylation and DNA methylation of the miR-200b/a/429 promoter.40 NEAT1 promotes the DNA methylation of the CpG island in the miR-129 gene.41 Both GIHCG and NEAT1 epigenetically silence target miRNA expression.40, 41 The miR-137 promoter has been shown to be hypermethylated in several tumor samples and cell lines, including lung cancer,42 colorectal cancer43 and GBM.44 An interesting line of investigation would be to evaluate whether XIST epigenetically regulates miR-137. The gene discussed is XIST; the disease is lung cancer.