DPP4 and neoplasm: Tumours from females with CRC also show different expression of genes involved in regulatory T-cell (Treg) function (higher GOT1 and GHR expression, lower DAB2, TNFRSF25 and LRRC32 expression), T helper 1 (Th1) response (higher expression of IL18R1, GBP1 and STAT4), co-stimulatory T-cell markers (higher expression of CD96, DPP4, GZMK and CCL14), and CD8+ cell exhaustion (higher expression of PD-L1 and TIGIT) compared with male tumours [54].