Harvey's Garden

Tumor markers

3 min read

MarkerTumor Associations
AFPHepatocellular carcinoma, Germ cell
CA 19-9Pancreatic
CA 125Ovarian
Carcinoembryonic antigen (CEA)Gastrointestinal (e.g., colorectal)
Human chorionic gonadotropinChoriocarcinoma, Germ cell
Prostate-specific antigenProstate

General Principle: Tumor markers are most useful for monitoring disease progression, response to treatment, and detecting recurrence. They are generally NOT used for screening or initial diagnosis due to low sensitivity and specificity.

Key Tumor Markers

  • AFP (Alpha-fetoprotein)

    • Associated Cancers:
      • Hepatocellular carcinoma (HCC).
      • Yolk sac (endodermal sinus) tumor and other non-seminomatous germ cell tumors.
    • Clinical Use: Used to screen high-risk groups (e.g., cirrhosis, hepatitis) for HCC. Also used for prognosis and monitoring treatment response in HCC and germ cell tumors.
    • Non-neoplastic elevations: Pregnancy, hepatitis, cirrhosis.
    • Mnemonic: “Awful Fat Producer” (AFP for HCC/Yolk Sac).

  • β-hCG (Human chorionic gonadotropin)

    • Associated Cancers:
      • Hydatidiform moles and Choriocarcinoma (Gestational Trophoblastic Disease).
      • Germ cell tumors (e.g., testicular cancer, especially non-seminomatous types).
    • Clinical Use: Diagnosis and monitoring of gestational trophoblastic disease and certain germ cell tumors.
    • Non-neoplastic elevations: Pregnancy (produced by syncytiotrophoblasts).

  • CA 19-9 (Carbohydrate antigen 19-9)

    • Associated Cancers:
    • Clinical Use: Primarily for monitoring treatment response in pancreatic cancer. Very high levels may suggest unresectable disease.
    • Non-neoplastic elevations: Biliary obstruction (cholangitis), pancreatitis, liver disease.
    • Note: Not produced in Lewis antigen-negative individuals (~5-10% of population).

  • CA 125 (Cancer antigen 125)

    • Associated Cancers:
      • Ovarian cancer (epithelial type).
    • Clinical Use: Monitoring response to therapy and detecting recurrence in ovarian cancer.
    • Non-neoplastic elevations: Endometriosis, pregnancy, pelvic inflammatory disease, pancreatitis, cirrhosis.

  • CEA (Carcinoembryonic antigen)

    • Associated Cancers:
      • Colorectal cancer (most common use).
      • Pancreatic, gastric, breast, lung cancers.
    • Clinical Use: Monitoring for recurrence of colorectal cancer after resection. A return to normal levels after surgery suggests complete resection.
    • Non-neoplastic elevations: Smoking (very common), IBD, pancreatitis, liver disease.

  • PSA (Prostate-specific antigen)

    • Associated Cancers:
      • Prostate cancer.
    • Clinical Use: Used for screening (controversial), staging, and monitoring for recurrence after treatment.
    • Non-neoplastic elevations: Benign prostatic hyperplasia (BPH), prostatitis, recent ejaculation, prostatic massage/biopsy.
    • Differentiating Factors: Free/total PSA ratio can help distinguish BPH from cancer; a lower ratio suggests malignancy. PSA velocity (rate of rise) is also useful.

  • Calcitonin

    • Associated Cancers:
      • Medullary thyroid carcinoma (MTC) (produced by parafollicular C-cells).
    • Clinical Use: Diagnosis, staging, and monitoring for recurrence of MTC. Very high levels (>100 pg/mL) are highly suggestive of MTC.
    • Key Association: All patients with MTC should be screened for MEN 2A and 2B syndromes (RET proto-oncogene mutation).
    • Non-neoplastic elevations: Chronic kidney disease, neuroendocrine tumors (e.g., carcinoid), some lung cancers.

  • LDH (Lactate dehydrogenase)

    • Associated Cancers:
      • Highly non-specific. Elevated in many cancers, especially those with high cell turnover, bulk, or necrosis (e.g., testicular cancer, lymphoma, melanoma, Ewing sarcoma).
    • Clinical Use: Primarily a prognostic marker indicating tumor burden and cell turnover.
    • Non-neoplastic elevations: Hemolysis (artifactual elevation), MI, liver disease, muscle injury.

Immunohistochemical markers

  • Vimentin
  • Desmin
    • Intermediate filament in the cytoskeleton of smooth and skeletal muscle cells
      • Rhabdomyosarcoma
  • Cytokeratin
    • Intermediate filament in the cytoskeleton of epithelial cells
      • Squamous cell carcinoma (e.g. of the skin or lung)

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