It has been proven that XIST is up-regulated in many tumors, including glioblastoma [68], hepatocellular carcinoma (HCC) [69], breast cancer (BC) [70], NSCLC [71], as well as nasopharyngeal carcinoma (NPC) [72], which suggests that it can become a valuable diagnostic biomarker specific for this group of diseases. Here, XIST is linked to breast cancer.