PRF1 and neoplasm: Differential gene expression between expanded and non-expanded T cells in both blood and tumor samples showed that expanded T cells are predominantly CD8+, having increased expression of cytotoxicity and T cell activation markers (NKG7, PRF1, GNLY, and GZMA/B/H/K/M), exhaustion markers (LAG3, TIGIT, and PDCD1), and major histocompatibility complex (MHC) class II genes (HLA-DRB1/DPA1/DPB1/DRA/DQA1/DRB5).