PCDH10 (protocadherin 10) is a calcium-dependent cell adhesion molecule belonging to the non-clustered protocadherin family, with diverse roles in virology, neurobiology, and cancer biology. As a primary function, PCDH10 mediates homophilic cell-cell adhesion and is predominantly expressed in the nervous system, where it supports neural circuit formation and maintenance 1. PCDH10 also functions as a cellular receptor for Western equine encephalitis virus (WEEV), an encephalitic arbovirus 2. Structurally, WEEV binds PCDH10 near the E1 fusion loop through shared determinants that also mediate lipoprotein class A domain binding, enabling engagement of multiple mammalian receptors 3. Notably, contemporary WEEV strains have lost mammalian PCDH10 binding while retaining avian receptor recognition, reflecting viral adaptation during enzootic circulation 2. Clinically, soluble PCDH10 protects mice from lethal WEEV challenge, suggesting therapeutic potential 4. Beyond virology, PCDH10 functions as a tumor suppressor gene. In hepatocellular carcinoma, PCDH10 upregulation inhibits cell proliferation and induces apoptosis by suppressing the PI3K/Akt signaling pathway 5. In endometriosis, reduced PCDH10 expression correlates with EZH2-mediated H3K27 methylation, promoting endometrial stromal cell invasion and migration 6. These findings indicate PCDH10 as a multifunctional molecule with potential biomarker and therapeutic applications in infectious disease, cancer, and reproductive pathology.