Fig. 2
From: Oncolytic virotherapy evolved into the fourth generation as tumor immunotherapy
The tumor specificity of oncolytic virotherapy. IA: Deletion of the required genes for virus replication in normal cells. IB: Deletion or inactivation of the required genes for virus replication and insertion of killer genes. IC: Transcriptional targeting. IIA: Retargeting strategies based on genetic manipulations of glycoproteins. IIB: T-cell activator. III: Translational targeting. IV: Hypoxic or drug induction. V: Intracellular restrictions by miRNA targeting