In spite of wide infection ability of adenovirus type 5 on tumor cells and normal non-malignant cells, MTT and in vivo assays showed that SG400-E2F/IL-15 and SG400-E2F both could selectively infect and kill breast cancer cells; and SG400-E2F/IL15 exhibited highest cytocidal effects on tumor cells. The gene discussed is IL15; the disease is breast cancer.