DANCR and retinoblastoma: Accumulating evidences have demonstrated the abnormal expression of DANCR in multiple cancers, including hepatocellular carcinoma, gastric cancer, colorectal cancer, pancreatic cancer, breast cancer, lung cancer, glioma, osteosarcoma, cervical cancer, bladder cancer, prostate cancer, nasopharyngeal carcinoma, esophageal squamous cell carcinoma, ovarian cancer and retinoblastoma.