Antibodies for tumor treatment are provided. More particularly are provided anti- VEGFR-2 antibodies, fragments and variants thereof that can be used for example, to inhibit/decrease angiogenesis and thus induce tumor regression in VEGFR-2 expressing tumors. In aspects, single domain anti-VEGFR-2 antibodies, fragments and variants thereof are provided to inhibit/decrease angiogenesis and induce tumor regression.