SP1 and gastric adenocarcinoma: Oxidative stress has been shown to increase VEGF production by activating VEGF promotor, located between -449 and -1, in macrophages [36], or through enhancing the binding of Sp1 and Sp3 transcription factors to proximal GC-rich motifs at -73/-66 and -58/-52 in gastric adenocarcinoma cells [37].