To corroborate our hypothesis that NO protects tumor cells from CDDP-induced apoptosis and to investigate the molecular mechanism underlying this event, U373 cells, natively deficient of NOS enzymes, were pre-incubated with the NO donor DETA-NO (20 μM, 1 h) before the addition of CDDP (50 μg/ml, 24 h). Here, NOS2 is linked to neoplasm.