NRP1 and alveolar rhabdomyosarcoma: Thus, the findings of a stimulating role of the PlGF/NRP1 pathway in pediatric cancers have led to an open-label Phase I clinical trial aimed to evaluate TB-403, a monoclonal antibody against PlGF, in pediatric patients with relapsed or refractory MBs, neuroblastomas, Ewing sarcoma, or alveolar rhabdomyosarcoma [124].