Diagnostic Accuracy of EBV C Promoter Methylation Kit in Nasopharyngeal Carcinoma

This study is evaluating the accuracy of a lab test that detects a specific type of DNA change (EBV C promoter methylation) in nasopharyngeal swab samples to diagnose nasopharyngeal carcinoma — a cancer in the back of the nose and throat associated with the Epstein-Barr virus (EBV). **You may be eligible if...** - You have one or more symptoms suggesting nasopharyngeal carcinoma - You have tested positive for EBV antibodies or EBV DNA - You have been diagnosed with another head and neck cancer or an EBV-related cancer - You need a test to rule out nasopharyngeal carcinoma during an endoscopy or imaging - You are able to give informed consent **You may NOT be eligible if...** - You have already been diagnosed and treated for nasopharyngeal carcinoma - Your nasopharyngeal carcinoma has relapsed or spread after treatment - A successful swab sample could not be collected Talk to your doctor to see if this trial is right for you.