Introduction:
Featured with vast heterogeneity, gastric cancer (GC) is one of the leading causes of cancer-related deaths. A specific prognostic model is necessary for the improvement of clinical treatment strategies. Hypoxia is a common feature in the tumor microenvironment that promotes tumor progression. However, the current evaluation of hypoxic tumor immune microenvironment in GC is still inadequate.

Material and methods:
With sequence data and single nucleotide variants data obtained from The Cancer Genome Atlas-STAD dataset as well as hypoxia- and immune-related genes acquired from MsigDB and ImmPort, a hypoxia-immune-based gene signature of gastric adenocarcinoma (STAD) was built by Cox regression analysis. Riskscore could be used as an independent prognostic factor.

Results:
Receiver operating characteristic curve and survival curve showed the accuracy of the model. Pearson correlation analysis showed that DUSP1, one of the hypoxia- and immune-related feature genes, was positively correlated with immune cell scores and immune-related function scores. In addition, low-risk group peers were found to be in higher immune infiltration status and had higher immunophenoscore as demonstrated by single-sample GSEA, indicating better response to immune checkpoint inhibitors (ICI) treatment among the low-risk group. q-PCR results showed that DUSP1, IGFBP1, CGB5, GPC3 and EGF were significantly highly expressed in STAD cells, while FAM3D and FGF8 were significantly down-regulated.

Conclusions:
Overall, our study not only paves the way for future studies focusing on hypoxia and immune microenvironment but also improves STAD patient’s prognosis and their response to immunotherapy.