Tumour Markers

Question 1

What are tumour markers?

Answer 1

Are substances produced either by, or in response to, tumour, and are present in blood or other tissue fluids and can be quantified

Question 2

What are the different classes of tumour markers? Can you give some examples?

Answer 2

• Cell-surface glyvoproteins
  
  • CA125
• Oncofetal proteins
  
  • HCG
  • a-feto-protein
• Enzymes
  
  • lactate dehydrogenase
  • acid phosphatase
• Hormones
  
  • thyroglobulin
  • ADH
• Immunoglobulins
• Nucleic acids

Question 3

When is is appropriate to order a blood test for tumour markers?

Answer 3

• They are relatively expensive test + chance of false positive result
• Not a substitute for careful Hx & examination
• Indicated when clinical suspician indicated by Hx and exam

Question 4

What tumour marker blood test in suspected prostate cancer? How specific is it?

Answer 4

• Prostate-specific antigen (PSA)
• Highly tissues specific and marked elevation in a man with disseminated bone metastases is usually diagnostis of prostate cancer

Question 5

What tumour marker blood test in suspected ovarian cancer? How specific is it? Level that is abnormal?

Answer 5

• CA125
• It is also elevated in endometriosis, menstruation and pregnancy
• 1% of normal individuals have an abnormal level too for no reason
• Level greater than 200 U/ml =abnormal

Question 6

What tumours markers are powerful determinants of outcome in testicular teratoma?

Answer 6

• Concentrations of HCG and aFP

Question 7

What is one of the most clinically useful features of tumour markers?

Answer 7

• Ability to indicate response to treatment
• In patient with elevated tumour marker, a reduction in the level of that marker whilst receiving treatment is highly suggestive or a response
• and vice versa, if level starts to increase again suggests relapse

Question 8

What cancer is cell surface antigen tumour marker commonly raised in/clinically used in?

Answer 8

• Elevated in a variety of tumour
• Common clinical used in setting of colorectal carcinoma

Question 9

What is alpha fetoprotein tumour marker used to detect? High levels predict?

Answer 9

• Glycoprotein that normally undetectable in normal individuals after first year of life
• Level moderately elevated in hepatitis
• High levels in hepatocellular carcinoma and cancers containing yolk sac (e.g. teratoma)
• High levels of aFP predict poor prognosis in malignancy

Question 10

When are Immunoglobulins measured as a tumour marker factor?

Answer 10

• measure of the paraproteinaemias e.g. in myeloma and Waldenstrom’s macroglobulinaema + non-Hodgkin’s lymphoma
• Measured in blood or their excretion can be measured in light chains in urine

Question 11

What is tumour marker is used in pancreatic cancer?

Answer 11

CA-19

Question 12

What tumour marker is used to monitor colorectal cancer?

Answer 12

Carcinoembryonic antigen (CEA)

Question 13

What is calcitonin a tumour marker for?

Answer 13

Medullary thyroid cancer