RBM15 and gastric cancer: RBM15-assisted XIST methylation is necessary for XIST-mediated silencing, thus revealing the first functional role for transcript-specific methylation directed by RBM15. RBM15 was also significantly upregulated in cancers and was associated with the prognosis of cancers, such as gastric cancer and chronic myelogenous leukemia (CML) (30, 31).