ENG and neoplasm: To confirm that tumor uptake of TRC105-based imaging probes measured by non-invasive imaging techniques was indeed CD105 specific, various control experiments (e.g. blocking study with unconjuagted TRC105, as well as the use of cetuximab as an isotype-matched control), in vitro/ex vivo studies (e.g. FACS and histological analysis), as well as biodistribution and ex vivo imaging studies were performed for validation purposes [24], [33], [34].