VACV thymidine kinase (VV-tk) gene was deleted to enhance tumor selectivity to address concerns of uncontrolled replication in non-target tissues, as described in our other OVV projects [11,12], and herpes simplex virus (type 1) thymidine kinase (HSV-tk) transgene was inserted for viral replication control. This evidence concerns the gene TKT and neoplasm.