Increased expression of RCN1P2, TPM3P9, and HSP90AB3P as pseudogenes in gastric cancer linked to proliferative, inflammatory and metastatic pathways through a competing endogenous RNAs network Running Title: Pseudogenes' role in gastric cancer pathogenesis

Abstract Introduction: Changes in the expression of pseudogenes have been demonstrated to play a role in the pathogenesis of various malignancies in studies. The goal of this study was to find pseudogenes with significant expression alterations in gastric cancer (GC) that could be implicated in the disease's development via the competing endogenous RNAs (ceRNAs) network. Methods: Pseudogenes, mRNAs, and microRNAs whose expression changes considerably in GC specimens were identified using the cancer genome atlas (TCGA) data. The ceRNAs network was constructed using the miRWalk, miRTarBase, and DIANA-LncBase databases. The cox regression test was performed to assess the correlation between candidate genes and patient prognosis using TCGA-derived GC clinical data. Finally, using the RT-qPCR method, the in silico results were evaluated using GC samples and adjacent normals. Results: The ceRNA network revealed that pseudogenes such as RCN1P2 , TPM3P9 , and HSP90AB3P were most connected to changed mRNAs and microRNAs in GC. The findings of subnet enrichment for each of the pseudogenes mentioned revealed that the related mRNAs are involved in cell proliferation, inflammation, and metastatic pathways. Furthermore, elevated expression of several mRNAs linked to potential pseudogenes was linked to a poor prognosis. The results of RCN1P2 , TPM3P9 and HSP90AB3P expression levels in TCGA and tissue samples showed that their expression increased significantly in GC. Conclusion: The expression of RCN1P2 , TPM3P9 , and HSP90AB3P is dramatically enhanced in GC. They can also influence the survival rate of GC patients by regulating pathways involved in cell proliferation, inflammation, and metastasis via the ceRNAs network.