Dormann and Deutsch (2002) used a hybrid cellular automaton to model the avascular growth of tumor cells. Vascularization is a hallmark of cancer, and vascular endothelial growth factor (VEGF) signaling can be therapeutically targeted. Alarcón et al. (2005) used a multiscale model for the vascular tumor growth accounting for tumor-normal cell interactions and vascularization through VEGF signaling. Owen et al. (2009) used a similar model to understand the dynamics of vascularization under different drug pressures to optimize drug efficacy. The gene discussed is VEGFA; the disease is neoplasm.