AK4 and head and neck squamous cell carcinoma: The expression of AK3L1 varies among TCGA tumors and is negatively correlated with the prognosis of cervical squamous cell carcinoma, endocervical adenocarcinoma, head and neck squamous cell carcinoma, head and neck squamous cell carcinoma HPV+, kidney chromophobe, liver hepatocellular carcinoma, lung adenocarcinoma, stomach adenocarcinoma, uterine corpus endometrial carcinoma, and uveal melanoma.