PVR and cancer: As shown in Figure 6, treatment of SKO-007(J3) cells with NCX4040 or with JS-K at micromolar concentrations (known to generate significant levels of intracellular NO in different cell lines, including MM [44-46]), upregulated the basal cell surface expression of PVR/CD155, confirming the data obtained using DETA-NO and suggesting the use of novel NO-releasing prodrugs as an additional class of regulators of the expression of DNAM-1 ligand in cancer cells.