Decreased accumulation of immune regulatory cells is correlated to the antitumor effect of IFN-γ overexpression in the tumor.

During mammary tumorigenesis, there is a profound tumor-induced immunosuppression and a progressive thymic atrophy associated with tumor development. IFN-γ has been shown to be effective in enhancing antitumor responses in several tumor models, however, how IFN-γ exerts its anti-tumor effect is largely controversial. In the present study we have used a mammary tumor model to investigate whether the levels of IFN-γ have an important role in the tumor-induced immuno-suppression as well as in the pathogenesis of the thymic atrophy.