CD8A and head and neck squamous cell carcinoma: No significant difference was detected in the percentage of CD8+ cytotoxic T cells in tumor samples (30.9 ± 18.7% of T cells) compared to non-cancerous mucosa (18.5 ± 6.9%), PBMC HC (24.6 ± 9.9%) or PBMC HNSCC (24.0 ± 14.0%; Figure 1B, right plot).