Tumour endothelial marker 1/endosialin-mediated targeting of human sarcoma.

•Tumour endothelial marker 1 (TEM1)/endosialin is a novel tumour target highly expressed in sarcoma and many tumours.•The article shows TEM1 is expressed in sarcoma (96%, n=203), and the pre-clinical development of a novel anti-TEM1 antibody.•We demonstrated the anti-tumour activity of the antibody drug conjugate against cancer cell lines in vitro and in vivo.•In addition, we show preliminary toxicology results and a possible mechanism of molecular escape.•These data represents a key milestone towards the clinical development of TEM1-targeted imaging and therapy.