Identification of associated molecular events in Helicobacter pylori infection and gastric cancer through integrated computational analysis of Microarray and RNA-Seq datasets

Abstract According to the World Health Organization, Gastric cancer (GC) is the third leading cause of death worldwide, where, the major precursor of cancer progression is infection with Helicobacter pylori. It has been reported that 50% of the total populace is infected with H.pylori, while in 80% the ulcer emerges in later stages of the infection. Although extensive separate analysis has been performed on H.pylori infection and GC data, however, there is a need to perform comparative analysis to identify the cross-talk between the conditions and to hunt significant molecular events that occurs during H.pylori induced GC. The aim of this multi-population study was to identify common molecular events and potential bio-markers against H.pylori induced GC. We performed microarray and RNA-seq analysis on publicly available H.pylori infection, gastritis, H.pylori induced GC and GC datasets to obtain Differentially Expressed Genes (DEGs). After obtaining the DEGs, integrative analysis, functional enrichment analysis and network biology approaches were utilized to identify common markers and hub genes between various disease conditions. Functional enrichment analysis revealed the DEGs of H.pylori infection, gastritis, H.pylori induced GC and GC were strongly associated with spliceosome, adherens junction, focal adhesion and ribosome. Being one of the common DEG, and highly interactive hub protein in the networks of all the conditions, translationally controlled tumour protein (TPT1) was identified as a significant predictive biomarker for early prognosis and diagnosis of H.pylori induced GC. Therefore, the mechanisms behind TPT1 should be further studied using in vitro cell-based functional assays, to determine its role in the progression of H.pylori induced GC.