It has the same mechanism of action as Delta-24-RGD, ICOVIR17 deletion of 24 base pairs in the Rb-binding domain of E1A for tumour-selective replication and RGD modification in the fibril to amplify tropism, except for two additional modifications: insertion of an E2F binding site in the E1A promoter and insertion of the SPAM1 gene encoding PH20 HA after the fibril, which is controlled by the major late promoter control (213). The gene discussed is RB1; the disease is neoplasm.