Neuro-2A cells were engrafted in the left flank of A/J mice and when tumours were palpable (∼3 days), mice were vaccinated every 2 days for a total of three doses with Neuro-IL2/IL12 or AJ-IL2/IL12 cells (n=16 per group) or with RPMI medium (n=6), by i.t. injection. This evidence concerns the gene IL2 and neoplasm.