Animals received a single intratumoral injection of either VRX-007 (circle symbols) or wild-type Ad serotype 5 (Ad5) (triangle symbols). Parallel groups of immunocompetent (solid symbols) and immunosuppressed (open symbols) animals were evaluated at 3, 9, and 22 days after injection. At each time point, the tumor, blood, and liver were harvested and processed for virus quantitation by tissue culture infectious dose 50 (TCID50) infectious titration and quantitative real-time PCR titration. The titers obtained (a) per tumor, (b) per ml of blood, (c) and per liver samples are shown. Left panels, TCID50 infectious titration. Right panels, quantitative real-time PCR titration. Each point represents the titer from one animal and the bars indicate the median for each group. The threshold for each assay is shown by the dashed horizontal line. Samples in which infectious virus was detected but was below the threshold of the assay are indicated by “+”. Samples in which no infectious virus was detected are indicated by “−.”