tumormarkers

Tumor markers, or cancer biomarkers, are substances that can be measured in body fluids or tissues and provide information about cancer. They can be produced by tumor cells or by normal cells in response to cancer. They are commonly proteins, but may also be nucleic acids, metabolites, or other molecules. Markers can be detected in blood, urine, tumor tissue, or other samples.

Clinical uses include screening and early detection in high-risk populations, aiding diagnosis and staging in conjunction with imaging and pathology, assessing prognosis, monitoring treatment response, and detecting recurrence. Some markers inform treatment decisions, for example by indicating likelihood of response to targeted therapies or immunotherapies. Marker panels and molecular tests are increasingly used to characterize tumors beyond traditional histology.

Common serum markers include PSA for prostate cancer, CA-125 for ovarian cancer, CA 19-9 for pancreatic and biliary cancers, CEA for colorectal and other cancers, and AFP for hepatocellular carcinoma and germ cell tumors. Others include hCG, thyroglobulin, and various genetic or molecular markers such as BRCA1/2 mutations, EGFR mutations, and tumor-derived DNA in blood (circulating tumor DNA).

Limitations include limited specificity—elevations can occur with benign conditions—and variable sensitivity, especially in early disease. Markers should not be used alone for diagnosis; results must be interpreted with clinical information and imaging. The field is increasingly moving toward non-invasive approaches such as liquid biopsy and multi-marker panels, with ongoing research to improve accuracy and utility.