SEMA3A and central nervous system cancer: However, more recently Sema3a has been found to bind to COS cells expressing Nrp2 (albeit 1.3 fold less than Nrp1 expressing COS cells), and a functional blocking antibody against Nrp2 removes the chemorepulsive effect of Sema3a on at least one human glioma cell line in vitro (Nasarre et al., 2009).