AFP and oropharyngeal carcinoma: Up till now, no serological tumor marker has been found to be specific to oropharyngeal carcinoma, so common biomarkers, including alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), neuron-specific enolase (NSE), cytokeratin 19, squamous cell carcinoma-associated antigen (SCC), CA125, CA724, CA199, and CA242, were examined in the blood samples of the patients at least 48 h before receiving PET/MR examination.