As IRF-7 and STAT-3 were also expressed by host cells, it could be hypothesized that transfer of VACV from cancer cells to host cells infiltrating the xenografts reproduced patterns observed in human cancer cells, while host's immune cells followed the classical up-regulation of pro-inflammatory pathways through STAT-1, IRF-1 signaling [18,42,51]. The gene discussed is STAT1; the disease is cancer.