CD8A and head and neck squamous cell carcinoma: [CD8+] / [CD4+/CD25+/CD127low] ratio was similarly decreased in tumor (4.4 ± 4.5) and mucosa (4.0 ± 2.7), being statistically significant between tumor samples and PBMC HNSCC (4.4 ± 4.5 vs. 7.8 ± 6.4; p < 0.05).