PRNP and head and neck squamous cell carcinoma: The level of PRNP mRNA was down-regulated in five types of cancers (colon adenocarcinoma, ovarian serous cystadenocarcinoma, rectum adenocarcinoma, uterine corpus endometrial carcinoma and uterine carcinosarcoma), whereas its level was up-regulated in other fives (lymphoid neoplasm diffuse large B-cell lymphoma, esophageal cancer, head and neck squamous cell carcinoma, pancreatic adenocarcinoma and thymoma).