FOXJ3 (forkhead box J3) is a transcriptional activator belonging to the forkhead box gene family that plays diverse roles in development and disease 1. During embryonic development, FOXJ3 is expressed in neuroectoderm, neural crest cells, and developing musculature, suggesting roles in neuronal and muscle development 2. In the brain, FOXJ3 regulates neuronal specification and cortical lamination by controlling PTEN expression, with pathogenic variants linked to focal cortical dysplasia and epilepsy 3. The protein exhibits context-dependent tumor-related functions: it acts as a tumor suppressor in colorectal cancer, where FOXJ3 expression is upregulated by ITGA5 circRNA through miR-107 sponging 4, but promotes oncogenic behavior in breast cancer by regulating Snail expression 5 and in tongue squamous cell carcinoma where it collaborates with THRA to promote cancer progression 6. FOXJ3 also supports glioma stem cell survival, as it is targeted by SOX2-regulated miR-425-5p 7. Additionally, FOXJ3 facilitates osteoclastogenesis in rheumatoid arthritis by promoting RGS1 transcription through enhancer RNA recruitment 8. These findings establish FOXJ3 as a versatile transcription factor with tissue-specific roles in development, neurological disorders, and cancer.