An early study conducted by Numasaki et al. demonstrated that the retroviral transduction of the IL-17 gene in cancer cells (MCA205 fibrosarcoma and MC38 colon adenocarcinoma) resulted in enhanced tumor growth in vivo while it had no effect on tumor cell proliferation in vitro. Tumors transduced with IL-17 exhibited significantly higher vascular density when compared to controls. Here, IL17A is linked to cancer.