Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 52 1 2023 01 07 128 137 Xiongbo Guo Department of Gastrointestinal Surgery, the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, P.R. China Wenbiao Zhu Department of Laboratory Medicine, Guangzhou Panyu Maternal Child Health Hospital (Guangzhou Panyu District He Xian Memorial Hospital), Guangzhou 511402, P.R. China 2022 07 05 2022 09 02 Background: To explore Arsenic trioxide (As2O3) and its regulated miR-885-5p/CDC73 signaling pathway involved in the development of gastric cancer. Methods: Fifty-two healthy patients and patients with gastric cancer were enrolled 2019-2020 in He Xian Memorial Hospital, Guangzhou, China. The patients with gastric cancer were divided into control group and As2O3 administration group. After 2 courses of treatment, their peripheral blood was collected to analyze the therapeutic effect. miR-885-5p expression in peripheral blood was analyzed by qRT-PCR. As2O3 was added into MGC-803 gastric cancer cell line at 0, 10, 20, 40 and 80 μmol/L. The proliferation rate and 48h IC50 value of gastric cancer cells were investigated by CCK-8, and the effect of As2O3 on miR-885-5p expression in the cells was analyzed. Results: After 4 weeks of treatment, the objective efficiency of control group and As2O3 administration group was 17.3% and 13.4%, respectively, without significant statistical difference. The overall benefit rate of As2O3 administration group was significantly higher than that of the normal treatment group (P=0.049). qRT-PCR experiment results found that miR-885-5p significantly highly expressed in peripheral blood in the As2O3 administration group, while miR-885-5p in gastric cancer was lower compared with normal people. Adding As2O3 to the gastric cancer cells could significantly inhibit miR-885-5p expression, while miR-885-5p in gastric cancer cells affected cell expression by targeted regulation, affecting cell proliferation. Conclusion: As2O3 may be used as a drug treatment program for gastric cancer, and mainly regulates the proliferation of gastric cancer cells by affecting the miR-885-5p/CDC73 target axis to participate in the development of gastric cancer.   https://ijph.tums.ac.ir/index.php/ijph/article/view/29208 https://ijph.tums.ac.ir/index.php/ijph/article/download/29208/7834