Overview of traditional and nontraditional tumor markers

Tumor markers include a wide spectrum of biomolecules produced by a wide variety of tumors or the body in response to the tumor. They play a significant role in screening, diagnosis, monitoring treatment response, surveillance, prognosis, and prediction of therapeutic response. During the past decades, the state of art on tumor marker research has shown interesting and promising results. For routine clinical use, some of the tumor markers are US Food and Drug Administration approved, although many emerging tumor markers are not. Ideally, tumor markers should have both high analytical sensitivity and specificity and high clinical sensitivity and specificity for cancer. Furthermore, the test methodology should be quick, reproducible, and minimally invasive, as well as minimally interfered. Therefore understanding the methodology limitations and the clinical relevance of traditional and nontraditional tumor markers is critical for optimal patient care.