NXPH1 and head and neck squamous cell carcinoma: A subset of three DMGs (Chr5q14.1, EMX1, and NXPH1), which showed the highest selectivity between control blood samples and cancer cell lines in ddPCR, was tested in different cancer tissues paired with adjacent normal tissues (frozen samples: PCa n = 14 vs. adjacent n = 24; lung cancer n = 20 vs. adjacent n = 22, invasive breast cancer n = 10 vs. adjacent n = 7, colorectal cancer n = 7 vs. 10, pancreatic carcinoma n = 17 vs. 23, hepatocarcinoma n = 12 vs. 10, squamous cell esophagus carcinoma n = 12 vs. 5, squamous cell head and neck carcinoma n = 13 vs. 8, and healthy donor blood n = 20).