IFNs have been documented to induce apoptosis in many tumor cells.24,52,53 The anti-apoptotic effects of IFN have been also documented.36–39,54 Type 1 IFN induced apoptosis linked with upregulation of bax gene expression,22,23 and activation of caspase-2 and caspase-3.55 The enhancement of HCASMC apoptosis by IFN-β was considered to be occurred by similar mechanisms to those in cancer cells. This evidence concerns the gene CASP2 and neoplasm.