Gastric cancer (GC) continues to rank among the primary causes of cancer-associated deaths worldwide, with few effective treatments available and incompletely elucidated molecular pathways. By conducting comprehensive analyses of TCGA and GEO databases, along with validation in clinical samples, we detected recurrent elevated expression of the transcription factor PHOX1 in GC specimens. This upregulation was strongly linked to higher T/M stages and unfavorable patient outcomes. We established that hypomethylation of the PHOX1 promoter, especially at the CpG site cg04123776, is responsible for its overexpression in GC. In vitro experiments showed that PHOX1 overexpression promoted GC cell growth, migration, and invasiveness, whereas PHOX1 silencing suppressed these oncogenic properties. Furthermore, orthotopic xenograft studies verified its role in facilitating liver metastasis from GC cells. At the molecular level, RNA sequencing, ChIP assays, and luciferase reporter experiments revealed that PHOX1 directly enhances transcription of the Nerve Growth Factor Receptor (NGFR). Rescue studies using NGFR-targeted siRNA and an ERK1/2 inhibitor confirmed that PHOX1 exerts its oncogenic effects through NGFR and the downstream ERK1/2 pathway. Overall, this work identifies PHOX1 as an oncogene responsive to methylation changes in GC, driving tumor advancement via NGFR transactivation. The PHOX1-NGFR-ERK1/2 pathway could represent a potential target for treating metastatic GC.
