Experimental work flow and sample usage.

Schematic diagram representing of type, distribution and usage of samples in different experimental procedures and etiological groups. N: Number of samples; PBL: Peripheral blood lymphocytes; HNSCC: Head and neck squamous cell carcinoma; IHC: Immunohistochemistry. HPV: Human papilloma virus; TOB: Tobacco. a. Normal specimens. b. Head and neck lesions.