Tax expression in all transgenic mice leads to oncogenesis and other less typical manifestations of HTLV-1 infection; however, leukaemia/lymphoma induction is rare and does not fully capture the disease environment, but it has been useful to elucidate the role that tax plays in the disruption of T cell function and establish its role as an oncogene [138,144]. The gene discussed is CNTN2; the disease is lymphoma.