VCAM1 and cancer: The ongoing Phase I/II clinical trial in unresectable, recurrent and refractory pulmonary OS will help to establish the safety and tolerability of anti-α4 antibody therapy or other therapeutic strategies targeting the VCAM-1/VLA-4 signaling axis in the pediatric and AYA cancer patient population, as well as open the door to additional combination studies in OS and other childhood and adult cancers.