The anti-tumor effects of IFN-α2a are mediated through upregulation of surface expression of major histocompatibility complex (MHC) class I molecules, enhancement of the proliferation of type-I helper T cells (Th1) (Belardelli 1995) and generation of cytotoxic T lymphocytes (CTLs) in specific antitumor immune responses (von Hoegen et al. 1990). The gene discussed is IFNA2; the disease is neoplasm.