PRF1 and neoplasm: The Cancer Genome Atlas (TCGA)-colon adenocarcinoma (COAD) dataset was also analyzed to identify cytotoxic T lymphocyte (CTL) scores using a set of 5 previously reported genes (CD8A, CD8B, GZMA, GZMB, and PRF1) as a surrogate of tumor infiltrating CD8+ T cells43.