CG0070, a genetically engineered oncolytic adenovirus was designed to selectively replicate in BC cells with defects in the retinoblastoma (Rb) tumor suppressor pathway, and concurrently produce granulocyte-macrophage colony-stimulating factor (GM-CSF) to stimulate immune-mediated anti-tumor effects (Burke et al., 2012).It uses the human E2F-1 promoter, which is active in cells with a compromised Rb pathway, to drive the expression of the key viral gene E1A, thereby ensuring that viral replication occurs selectively in tumor cells lacking functional Rb. Here, E2F1 is linked to neoplasm.