ELF4 (E74 like ETS transcription factor 4) is a transcriptional regulator that functions as both an activator and repressor of inflammatory responses. The protein binds to DNA sequences containing ETS consensus sites and regulates transcription of multiple target genes 1. ELF4 plays a critical role in immune system function by sustaining expression of anti-inflammatory genes such as IL1RN while limiting upregulation of pro-inflammatory mediators including IL1B, IL6, TNFA, and neutrophil chemoattractants 1. The transcription factor also controls expression of TREM1, a cell surface receptor involved in amplifying inflammatory responses 1. Loss-of-function mutations in ELF4 cause DEX (deficiency in ELF4, X-linked), an autoinflammatory syndrome characterized by recurrent oral ulcers, inflammatory bowel disease-like symptoms, and hyperinflammatory macrophage responses 12. Patients with DEX typically present in early childhood with fever, mucosal ulcerations, and elevated inflammatory markers 2. Treatment often involves anti-TNF therapy, IL-1 blockade, or corticosteroids 3. In cancer contexts, ELF4 overexpression correlates with poor prognosis and increased drug resistance across multiple tumor types 4.