[Regulation of the Tumor Microenvironment through HER2 Signaling-Insights from Gastric Cancer Cases with Heterogeneous HER2 Overexpression].

HER2, a member of the human epidermal growth factor receptor(HER)family, exhibits gene amplification, protein overexpression, or both in 13-27% of gastric cancer(GC)cases. Through the activation of downstream Akt and ERK pathways, HER2 promotes the survival and proliferation of gastric cancer cells. The impact of HER2 signaling on the tumor microenvironment(TME)in GC remains unclear, and the heterogeneity of HER2 overexpression in GC tissues is considered a contributing factor. In this study, we focused on differences in the TME between HER2-positive and HER2-negative areas in HER2-positive GC and found that HER2 signaling, particularly the HER2-Akt cascade, may suppress stimulator of interferon genes (STING)expression and reduce CD8+ T cell infiltration in tumor cells. Overall, our findings suggest the potential for a novel therapeutic approach to activate the anti-tumor immune response in HER2-positive GC.