TKT and neoplasm: A bioluminescence assay was conducted on day 2, post single-dose IT injection of either OTS-412 or VVtk- in RenCa tumor-bearing mice on day 0 to examine the impact of the HSV-tk insertion on the virus level in tumor (Figure 3A); the luciferase signal levels were not statistically different between the two viruses (Figure 3B).