Tumor markers are biological substances that can be detected in the blood, urine, or body tissue of some tumor patients. Although some tumor markers may aid in the diagnosis of cancer, they are primarily used for monitoring treatment response and detecting cancer recurrence. Tumor markers are not reliable screening or diagnostic markers due to their low sensitivity (i.e., not elevated in all cancer patients) and low specificity (i.e., also elevated in benign, noncancerous conditions or otherwise healthy patients). The majority of tumor markers that are used in the clinical setting can be detected in the blood. A number of tumor markers can be detected on tissue histopathology. They are also referred to as immunohistochemical markers and can be detected using immunohistochemical techniques. Gene mutations and patterns of gene expression are also increasingly being used as tumor markers.
- Definition: substances (hormones, enzymes, antigens, immunoglobulins, glycoproteins) that can be detected in the blood, urine, or body tissue of some cancer patients
- Detect cancer (does not confirm diagnosis!)
- Predict therapeutic responses
- Monitor the effectiveness of cancer treatment
- Detection of cancer recurrence and screening
Tumor markers are generally not used to screen for or diagnose cancer. However, once cancer has been diagnosed via biopsy, tumor markers can be used to predict therapeutic responses and monitor the effectiveness of cancer treatment.
|Common tumor markers |
|Tumor marker||Associated conditions|
|Alpha fetoprotein (AFP)|
Carcinoembryonic antigen (CEA)
|Placental alkaline phosphatase || |
|Neuron specific enolase (NSE)|
|CA 15–3 and CA 27–29|
|S-100 protein (S100A) and (S100B)|
|β2 microglobulin (β2M)|
|Squamous cell carcinoma antigen (SCC) antigen|
|DCP (Des-gamma-carboxy prothrombin)|
“Alpha male, HE is a MAN:” the cancers associated with alpha-fetoprotein are Hepatocellular carcinoma, Endodermal sinus tumor (yolk sac tumor), Mixed germ cell tumor, Ataxia-telangiectasia, and Neural tube defects.
β-hCG: Hydatidiform mole, Choriocarcinoma, and Gestational trophoblastic disease are associated with the marker
Gene mutations and changes in gene expression
|ALK gene rearrangement|
|EGFR gene mutation|| |
|Estrogen and progesterone receptors|
- Definition: Antigens on the surface of cells that can be detected via tissue histopathological evaluation.
- Clinical relevance
|Overview of immunohistochemical markers |
|Marker||Natural occurrence||Occurrence in tumors|
|Chromogranin A|| |
|TRAP|| || |
|CD45|| || |
DesMin is associated with muscle tumors like rhabdoMyosarcomas.
ViMEntin is associated with MEsenchymal tumors.
GFAP stains neuroGlial cells, which are affected in Glioblastomas.