Tumor markers

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.

For details regarding specific carcinomas and the corresponding tumor markers, see the individual cancer articles.

• Definition: substances (hormones, enzymes, antigens, immunoglobulins, glycoproteins) that can be detected in the blood, urine, or body tissue of some cancer patients
• Clinical use
  • Detect cancer (does not confirm diagnosis!)
  • Predict therapeutic responses
  • Monitor the effectiveness of cancer treatment
  • Detection of cancer recurrence and screening
• Limitations
  • Not all patients with cancer have elevated tumor markers (low sensitivity)
  • Not all patients with elevated tumor markers have cancer! (low specificity)

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.

References:^{[1][2][3][4][5]}

“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

Abnormal patterns of gene expressions and gene mutations from tissue samples are increasingly being used as tumor markers.

References:^[9]

• Definition: Antigens on the surface of cells that can be detected via tissue histopathological evaluation.
• Clinical relevance
  • Immunohistochemical markers provide information about the origin and immunohistochemical characteristics of tumor cells (e.g., distribution of protein expression).
  • The presence or absence of certain immunohistochemical markers can help establish the prognosis of disease.

DesMin is associated with muscle tumors like rhabdoMyosarcomas.

ViMEntin is associated with MEsenchymal tumors.

GFAP stains neuroGlial cells, which are affected in Glioblastomas.