RB1 and neoplasm: MAV-1 is a murine oncolytic adenovirus comparable to ICOVIR-5 [1]: MAV-1 and ICOVIR-5 have genetic modifications that allow them to replicate preferentially in cells in which retinoblastoma (Rb) pathway is deregulated [15], a common feature of advanced human cancers (including neuroblastoma, NB) but not in healthy cells; MAV-1 and ICOVIR-5 are also able to replicate in MSCs, although at significant lower levels compared to replication in tumor cell lines [1] (Supplementary Figure 1A, 1B, 1C).