FN1 and cancer: By taking advantage from these unique structural and physicochemicalfeatures, nanotechnologists have exploited nanocages constituted onlyby H-chains of Fn (HFn) for drug delivery, accomplishing the loadingof different types of compounds, like chemotherapeutics or fluorescentdyes.5 More importantly, the ability todirectly target the human transferrin receptor 1 (TfR1), which isoverexpressed in several cancer types, increases the attractivenessof HFn in the context of cancer treatment.3