OncoSeek®, a customized panel of seven selected protein tumor markers (PTMs) including AFP, CA125, CA15-3, CA19-9, CA72-4, CEA, and CYFRA21-1, quantified them on Roche cobas e411 instrument performing for 12 common cancers early detection. It established a multivariate algorism for cancer detection by integrating the measurement of these seven PTMs and age of the subject which was empowered by artificial intelligence technology. The results showed that OncoSeek significantly outperformed the traditional clinical method, representing a novel blood-based test for multiple cancer detection.