Tumour-targeting immunocytokines based on IL2 have previously been demonstrated to mediate the infiltration of immune cells into the tumour mass, with natural killer (NK) cells as the main mediator of therapeutic activity (Reisfeld and Gillies, 1996; Carnemolla et al, 2002; Mårlind et al, 2008; Schliemann et al, 2009). Here, IL2 is linked to neoplasm.