CD8A and neoplasm: A possible explanation for this unexpected phenomenon is that being regulatory cells, CD4+Foxp3+Tregs may inhibit the active inflammatory process, the production and action of growth factors and pro-inflammatory cytokines directly related to promoting tumour growth; they may also significantly support the mechanisms related to the activity of CTLs and induce a high CD8+/Foxp3+ ratio in HNSCC [132,133,134].