Among these we analyzed CD133, N-Myc, CCND2, E2F1 and E2F2, Bcl-2 and IAP-2, since they are overexpressed in 3AB-OS cells (8,11) and many of them were found to be frequently overexpressed in tissues of osteosarcoma patients (29–35). The gene discussed is E2F1; the disease is osteosarcoma.