HRAS and neoplasm: Croix et al. to be overexpressed on the tumor vasculature and to play a role in tumor angiogenesis [18]; however, in 2001, a study by Duesbery et al. demonstrated that in vitro treatment of V12 H-ras-transformed NIH 3T3 cells or in vivo injection of anthrax lethal toxin ((LeTx): PA plus lethal factor (LF)) into athymic nude mice implanted with ras-transformed cells led to a strong antitumor response and, in some cases, caused complete tumor regression of xenografts [21].