Several growth factors, cell differentiation, cellular adhesion, molecules and transcription factors were expressed 14 days in the apical periodontitis area upon LPS inoculation: Tgfbr1, Igl1r, Vegfa, Ctsk, Mmp9, Nfkb1, Smad3, Sox9, Cd36, Icam1 and Vcam1. Vascular endothelial growth factors (Vegf) and their receptors control vasculogenesis and are also involved in bone resorption in apical periodontitis.3 The gene discussed is MMP9; the disease is periapical periodontitis.