Genetic deletion of the EGFR ligand epigen does not affect mouse embryonic development and tissue homeostasis

► Epigen is the least characterized epidermal growth factor receptor (EGFR) ligand. ► Epigen-deficient mice are viable and show no defects in organ structure and function. ► Epigen is not essential for development and tissue homeostasis. ► This study completes the genetic analysis of EGFR ligand function in mice.