Components of the IFN-gamma signaling pathway in tumorigenesis.

Many features of the interferon gamma (IFN-gamma) signaling pathway would suggest that it is anti-tumorigenic. The IFN-gamma signaling pathway leads to apoptosis and to the expression of immune function proteins that could cooperate with T cells in the destruction of tumor. Various lines of experimental approach have, in general, supported the hypothesis that the IFN-gamma signaling pathway is anti-tumorigenic. However, data also indicate that the idea that the IFN-gamma signaling pathway is exclusively anti-tumorigenic is too simplistic. Also, to date, very little of the knowledge regarding the anti-tumor effects of the IFN-gamma pathway has been useful in the prognosis or therapy of cancer. This review summarizes the current state of knowledge regarding the IFN-gamma signaling pathway in tumorigenesis, with an emphasis on MHC class II induction in tumor cells and the induction of apoptosis in tumor cells. The review also indicates some future areas of investigation that offer hope for applying this knowledge in reducing cancer mortality.