This study identified five TMEFF2 interacting proteins in AGS gastric cancer cells, including tyrosine-protein phosphatase non-receptor type 6 (SHP1), Ras GTPase-activating protein-binding protein 1 (G3BP1), heterogeneous nuclear ribonucleoprotein K (HNRPK), splicing factor 1 and ubiquitin carboxyl-terminal hydrolase 4 (USP4). Here, USP4 is linked to gastric cancer.