Histological analysis of tumour sections showed extensive leukocyte infiltration in tumours from animals vaccinated with Neuro-IL2/IL12 or AJ-IL2/IL12 compared to negligible staining for leukocytes in control tumours, suggesting that the fibroblast vaccine recruits immune effector cells to the tumour site as effectively as the tumour cell vaccine. This evidence concerns the gene IL2 and neoplasm.