Regarding the molecular mechanism underlying the oncolytic adenovirus-mediated MCL1 suppression, we demonstrated that OBP-301 upregulated MCL1-targeted miRNAs, such as miR-15, miR-16 and miR-29, and miR-29 overexpression efficiently suppressed MCL1 expression in human osteosarcoma cells. Here, MCL1 is linked to osteosarcoma.