Isogenic littermates, Cre+ (SOD3 overexpression in EC; SOD3EC-Tg) or Cre− (no ectopic SOD3 expression), were inoculated with LLC cells, and EC-SOD3 overexpression was induced by two tamoxifen injections; higher tamoxifen doses impaired tumor angiogenesis, independently of SOD3 induction. The gene discussed is SOD3; the disease is neoplasm.