ITGB2 has potential as a prognostic factor for the immune microenvironment of gastric cancer tumours and as an indicator of tumour microenvironment remodelling

In recent years, correlation studies of immune infiltration in gastric cancers, such as STAD have attracted much attention. However, the correlation between the expression of the immune factor ITGB2 and the malignant features of immune infiltration and gastric cancer has rarely been reported. Batch RNA-seq and scRNA-seq data were combined to screen for differentially expressed genes using software packages and machine learning. Data from the TCGA and five GEO databases were used to investigate the expression levels of ITGB2 in patients with STAD, and the correlation between ITGB2 expression levels and gastric cancer progression was explored and validated. The expression of ITGB2 was validated through rt-qPCR and Western blot analysis in cell experiments. Several algorithms were used to analyse the correlation between ITGB2 and immune infiltration in patients with STAD. The study predicted chemotherapy and immunotherapy responses for subgroups with high and low expression of ITGB2. Gene knockdown was performed on gastric cancer cells to confirm its correlation with immune checkpoint ligand-related genes and conduct preliminary validation of its signaling pathways. Furthermore, migration, invasion, and proliferative abilities were assessed using the Transwell assay and CCK-8 assay. This study revealed that ITGB2 is significantly elevated in gastric cancer, while increased levels of ITGB2 were linked to worse clinical outcomes and prognosis in STAD patients. Lower expression levels of PD-L1 were observed concurrently in the ITGB2 knockdown group. Moreover, gastric cancer patients with high levels of ITGB2 had better responses to immunotherapy. Finally, prognostic features using LASSO regression demonstrated satisfactory prognostic predictive ability. ITGB2 expression is a promising potential immune-related biomarker for STAD, and the prognostic model and immunotherapy sensitivity prediction based on ITGB2 may offer new strategies for individualized treatment and may aid in identifying patients who may benefit from immunotherapy, although further clinical validation is warranted.