NQO1 and head and neck squamous cell carcinoma: The NQO1 mRNA expression levels were inversely linked with most immunological checkpoint molecules, including thyroid carcinoma, testicular germ cell tumors, lung adenocarcinoma, rectum adenocarcinoma, head and neck squamous cell carcinoma, lung squamous cell carcinoma, stomach adenocarcinoma, stomach and esophageal carcinoma, bladder urothelial carcinoma, colon adenocarcinoma, colon adenocarcinoma/rectum adenocarcinoma esophageal carcinoma, cervical squamous cell carcinoma and endocervical adenocarcinoma, and esophageal carcinoma.