Eps8, also known as Epidermal growth factor receptor pathway substrate 8, was initially identified as a substrate for the kinase activity of the epidermal growth factor receptor (EGFR). It has a domain structure typical of a signaling molecule, including a putative N-terminal PTB domain, a central SH3 domain, and a C-terminal "effector region". Eps8 participates in EGFR signaling through Rac and endocytosis through Rab5 by engaging in different protein complexes. It binds to Abi1 or RN-tre via its SH3 domain, and the former helps activate Rac while the latter inhibits EGFR internalization [1].

Numerous studies have shown Eps8 to be overexpressed in most malignant tumors. Loss-of-function experiments in cells have demonstrated that Eps8 promotes the proliferation, migration, and invasion of glioblastoma and multiple myeloma cells, and also enhances the uncoating of influenza A virus [2,3,4]. In non-small-cell lung carcinoma cells, knockdown of Eps8 inhibits cell growth, induces cell-cycle arrest, and increases the therapeutic effects of cisplatin [5].

In conclusion, Eps8 is a crucial signaling molecule involved in multiple biological processes and disease conditions. Its overexpression in various cancers and role in promoting tumor-related phenotypes make it a potential biomarker and therapeutic target. Functional studies, especially through loss-of-function experiments, have provided insights into its role in cancer development and viral infection, offering new perspectives for disease treatment.