Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 51 10 2022 10 04 2231 2243 Darebai Redati Department of Gastrointestinal Surgery, The Affiliated Cancer Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, China Xinhui Yang Department of Gastrointestinal Surgery, The Affiliated Cancer Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, China Cheng Lei Department of Gastrointestinal Surgery, The Affiliated Cancer Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, China Lin Liu Department of Gastrointestinal Surgery, The Affiliated Cancer Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, China Lei Ge Department of Gastrointestinal Surgery, The Affiliated Cancer Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, China Haijiang Wang Department of Gastrointestinal Surgery, The Affiliated Cancer Hospital of Xinjiang Medical University, Urumqi 830011, Xinjiang, China 2022 03 04 2022 05 19 Background: The RAD51 recombinase is involved in homologous recombination and DNA repair. However, the association of RAD51 with the prognosis of adenocarcinoma at the gastroesophageal junction (ACGEJ) is not clear. We aimed to investigate the association of RAD51 with ACGEJ prognosis. Methods: The difference in the expression level of RAD51 between ACGEJ tumors and control tissues in the microarray datasets (GSE159721, GSE74553, and GSE96669) were compared. The online Kaplan-Meier plotter survival analysis and meta-analysis were used to analyze the association of RAD51 with overall survival in pan-cancers. MiRNAs targeting RAD51 were identified and their expression profiles in ACGEJ tumors were analyzed. Functional enrichment analysis was performed for miRNAs of RAD51. Results: RAD51 was upregulated in ACGEJ tumors compared with control tissues (P < 0.05). High RAD51 level was correlated with a poor prognosis in stomach adenocarcinoma and esophageal cancer. The meta-analysis showed that high RAD51 level was correlated with a poor prognosis in TCGA pan-cancers (P = 0.03). Six regulatory miRNAs of RAD51, including hsa-miR-182, hsa-miR-221, and hsa-miR-34a, were downregulated in ACGEJ tumor tissues and were associated with pathways including “fatty acid biosynthesis” and “viral carcinogenesis”. Conclusions: RAD51 is a potent prognostic biomarker in ACGEJ. MiRNAs including hsa-miR-182, hsa-miR-221, and hsa-miR-34a might play crucial roles in ACGEJ by regulating the RAD51 gene.   https://ijph.tums.ac.ir/index.php/ijph/article/view/28057 https://ijph.tums.ac.ir/index.php/ijph/article/download/28057/7740