IL17A and nasopharyngeal carcinoma: While the association of high CD8+ TIL density with a poorer prognosis may seem counter-intuitive, as CD8 is a marker of cytotoxic T-cells, it is important to note that CD8 also marks CD8+CD25+FOXP3+ regulatory T cells and IL-17-producing CD8+ T-cells (Tc17 cells), both of which have been observed in NPC tumours (129).