Induction of protective antitumor immunity. Mice (10 mice/group) were immunized with 10 μ g qVEGFR (•), mVEGFR (▪), vehicle (ALUM; ▴) alone, or PBS alone (nonimmunized; ⋄) once a week for 4 weeks. Mice were then challenged subcutaneously with 1 × 10⁶ CT26 (A), LL/2 (B), or Meth A cells (C) 1 week after the fourth immunization. There was an apparent difference in tumor volume between qVEGFR-immunized and control groups. Results are expressed as mean ± SEM.