Rekers hypothesised that tumour cells outside the radiation field would also be eliminated by this combination treatment (abscopal effect) and that tumours cannot be formed again after re-challenging cured animals (memory effect).  In fact RT+L19-IL2 was able to cure 100% of primary tumours and was associated with an increased percentage of CD8+ T cells inside these irradiated tumours. Here, IL2 is linked to neoplasm.