FN1 and neoplasm: We engineered nanobody-IL-2 immunocytokines targeting the tumor ECM that are small in molecular size (∼32 kDa), possess a range of binding affinities to tumor-associated, EIIIB-containing FN (untargeted, nanomolar, and picomolar) and administered them via different routes (i.v. and i.t.)into immunocompetent mice.