For example, FOXD2-AS1 was found to be overexpressed in bladder cancer tissues, which further promoted bladder cancer progression and recurrence through forming a positive feedback loop with Akt and E2F1 (12); in addition, Xu et al. have reported that overexpression of FOXD2-AS1 contributed to carcinogenesis of gastric cancer, and predicted poor prognosis in gastric cancer patients (13). This evidence concerns the gene E2F1 and gastric cancer.