Double-labeling of tumor cross sections with antibodies against human CD8 and human IFNγ (Figure 7A) followed by counting of CD8+ (Figure 7B) and IFNγ+ (Figure 7C) T cells clearly show marked infiltration of human CD8+ cells capable of releasing IFNγ into the tumor of PDX mice after treatment with p40 mAb, but not control IgG. This evidence concerns the gene IFNG and neoplasm.