Remarkably, a study carried out by the National Cancer Institute, NCI-USA, with targeted RGD4C-AAVP-TNFα carrying the gene for the cytokine tumor necrosis factor alpha (TNFα), showed specific delivery of TNFα in natural tumors in pet dogs, resulting in eradication of aggressive and sizeable tumors such as fibrosarcoma in a few cases [9]. Here, TNF is linked to fibrosarcoma.