Corroboration of BLI analysis was also provided by fluorescence confocal microscope observation of mouse brain sections that showed (Fig. 5) the presence of red fluorescent Rluc-R-tTK-hAMSCs evenly distributed throughout the tumor implantation site mixed with green fluorescent tumor cells, at T = 0 before starting GCV treatment (Fig. 5A). This evidence concerns the gene TTK and neoplasm.