These findings indicate that, as observed previously with Ad.5-CTV [44,58,59,60], in Ad.5-TCTV-infected cells the truncated PEG-promoter allowed adenovirus replication specifically in cancer cells, whereas normal cells were protected from growth inhibition because of the absence of adenovirus replication (due to reduced levels of AP1 and PEA3 transcription factors) [55,62], and tumor suppressor (mda-7/IL-24) transgene expression. This evidence concerns the gene ETV4 and cancer.