PLVAP and malignant glioma: The intergeneric poliovirus CD155 receptor with the HRV2 IRES is known as prototype intergeneric poliovirus chimera PV1 (RIPO) which exhibits reduced replication in neural cells and does not result in poliomyelitis [21-23]. Intratumoral PV1 (RIPO) injection is necessary for malignant gliomas to demonstrate anti-tumour activity.