PRF1 and neoplasm: We used IRF1 mRNA as a marker of IFNγ-regulated MHC class I antigen presentation pathway in tumor cells, CD8 as activated cytotoxic T cell marker, and GZMA and PRF1 as immune cytolytic activity markers to analyze if the IFNγ signaling pathway activity is correlated with cytotoxic T cell-associated cytolytic activity.