PVR and neoplasm: The tumor selectivity of picornaviruses arises from the overexpression of the virus entry receptors on malignant cells: intercellular adhesion molecule-1 and/or decay-accelerating factor (CVA21),130 anthrax toxin receptor 1 and sialic acids (SVV),131 CD155 (PVSRIPO),132 and integrin α1β2 (echoviruses).133