1 Tumour Markers Flashcards

1
Q

What is an uncontrolled growth of cells that forms a solid mass or tumour referred to as?

A

Neoplasm

Cancer, broad term.

Can spread to other areas of the body.

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2
Q

What are the different tumour stages?

A

Stage I - localized
Stage II - invasion of tumour through epithelial cells
Stage III - migration of tumour into regional lymph nodes
Stage IV - metastasis and invasion of tumour into distant tissues.

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3
Q

What are the five reasons tumour markers are tested?

A
  1. Aids diagnosis in symptomatic patient.
  2. Cancer prognosis - clinical outcome
  3. Tumour stages, severity and spread
  4. Monitoring treatment
  5. Dectecting recurrence or remission
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4
Q

What are other things Doctors used in addition to tumour markers to assess cancer?

A

In addition to tumour markers, doctors also use the following to diagnose cancer:

  1. Clinical signs
  2. Symptoms
  3. Histology
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5
Q

What are the different types of testing for tumour markers?

A
  1. Immunological methods (use antigens to confirm cell types)
  2. Molecular methods (differentiate malignant from benign, personalized medicine, etc.)
  3. Biochemical methods (enzymatic)
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6
Q

Can you name at least 3 ideal Tumour Marker characteristics?

A
  1. Measured easily and reliably
  2. Cost effective
  3. High analytical sensitivity and specificity
  4. Quantifiable
  5. Reflects tumour burden
  6. Results influence patient care and outcome
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7
Q

Can a tumour marker be used to effectively screen asymptomatic populations?

A

No, although there are debate about some (e.g. PSA). Tumour markers are not seen as an effective screen in the asymptomatic population.

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8
Q

What are the different types of tumour markers?

A
  1. Enzymes - correlate with tumour burden
  2. Hormones - secreted by tumours (or cause excess secretion from endocrine tissues)
  3. Oncofetal Antigens - was once present in embryonic fetal tissue now in the cancer
  4. Cancer or Carbohydrate Antigens - specific antigens are related to cancers, e.g. CA 125, CA 15-3, etc.
  5. Proteins - monoclonal antibodies
  6. Oncogenes - genes that under certain circumstances can transform a cell into a tumour cell (age, chemical exposure, vrus, etc.)
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9
Q

What is the typical blood collection tube for tumour markers?

A

Lithium Heparin Plasma Separator Tube

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10
Q

What interfering substances should the technician be aware of when measuring tumour markers? What precautions can be taken?

A

When using immunoassays, erroneous results could occur if the patient is on high biotin doses.

Do not collect samples until at least 8 hrs after the last dose.

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11
Q

What does the tumour marker alpha fetoprotein assist in?

A

Assists in the management of patients with germ cell tumours or hepatocellular carcinoma.

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12
Q

Where is alpha fetoprotein synthesized?

A

Synthesized by the liver, yolk sack and the gastrointestinal tract of the fetus.

After birth, AFP concentrations decline and are not normally present in healthy adults.

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13
Q

How is alpha fetoprotein measured in the laboratory?

A

Plasma (sample type)

Immunoassay method.

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14
Q

What type of tumour marker is alpha fetoprotein?

A

Oncofetal antigen

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15
Q

What does carcinoembryonic antigen (CEA) used for?

A

Carcinoembryomic antigen (CEA) is used to:

  1. Monitor colorectal cancer treatment.
  2. Identify recurrence
  3. Aid in staging and assessing metastasis.
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16
Q

What is the origin of CEA (carcinoembryonic antigen)?

A

CEA is an oncofetal antigen found in embryonic tissue and associated with certain types of cancers (e.g. colorectal cancer).

17
Q

What populations (patients) can CEA also be elevated in?

A

Can be elevated in patients with COPD, colitis, hepatitis, and in smokers.

18
Q

What sample type and testing method is used to measure CEA?

A

Plasma (sample type)

Immunoassay method.

19
Q

What is Cancer Antigen 15-3 used for as a tumour marker?

A

Monitors breast cancer treatment and to detect recurrence.

20
Q

What is BRCA1 and BRCA2 used for as a tumour marker?

A

BRCA1 and BRCA2 used for:

To identify risk of breast and ovarian cancer in particular.

Also risk of pancreas and prostate cancer.

21
Q

What is the carbohydrate antigen 19-9 (CA19-9) used for as a tumour marker?

A

Monitor pancreatic cancer treatment and detect recurrence.

22
Q

What is the cancer antigen 125 (CA125) used for as a tumour marker?

A

Cancer antigen 125 (CA125) used for:

Monitoring ovarian cancer treatment and to detect recurrence.

Note: > 80% of ovarian cancer patients have elevated CA125 levels. Correlated with tumour burden and extent of disease.

23
Q

What is hCG (Chorionic Gonadotropin) used to detect as a tumour marker?

A
  1. Prognostic indicator for ovarian cancer.
  2. Diagnostic marker for testicular cancer.
  3. Detection of gestational trophoblastic disease.
24
Q

When measuring hCG as a tumour marker what specific components are measured?

A

Measure free beta unit and whole molecule hCG.

25
Q

What tumour marker is considered the most specific tumour marker?

A

Prostate Specific Antigen (PSA)

26
Q

What is prostate specific antigen used to monitor?

A

PSA:

Used to monitor patients with a history of prostate cancers for recurrence and response to treatment.

27
Q

What components of PSA are measured when assessing the tumour marker?

A

Free and complexed PSA.

Note: One can look at either.

Also Total PSA = free PSA + bound PSA can be used to screen for prostate cancer.

28
Q

What is percent-free PSA used for in evaluation?

A

Percent-free PSA = fPSA/tPSA x 100%

Distinguishes prostate cancer from benign prostatic conditions.

Only used on patients with symptoms.

29
Q

If total PSA is used for screening prostate cancer, when is it recommended to test for free PSA?

A

When Total PSA is between 4 and 10, then get tested for free PSA.

30
Q

What screening programs are done in lieu of not using tumour markers in the general asymptomatic population?

A

Breastcheck, age 50-74, screening mammogram every 2 years
CervicCheck, age 21-69, pap test, every 3 years
Colon Check, age 50-74, home test, every 2 years

31
Q

What does Fecal Occult Blood Test (FOBT) screen for and what does it look for in the sample?

A
  1. Screens for colorectal cancer (early).

2. Looks for blood in stool.

32
Q

How many samples does the patient collect for FOBT and what are the things for them to avoid when doing so?

A
  1. Collect 3 separate stool samples.
  2. Avoid:
    a) Don’t let the stool hit water
    b) Vitamin C
    c) Collect 3 days before or after menstrual period.
33
Q

What all does the patient do with FOBT?

A

Collect the sample (3 stools)

Smear on card and mail in.

34
Q

What is FIT?

A

FIT is Fecal immunochemical Test.

Note: Also called immunochemical fecal occult blood test (iFOBT)

35
Q

What is the advantage and disadvantages of FIT over FOBT?

A

Advantages are:
1. Newer and considered to be more sensitive
2. Only 1 stool sample required (as opposed to 3)
3. No dietary restrictions needed.
Disadvantage
1. Expensive and not widely used.

36
Q

What is the technical basis of the FOBT test?

A

Pseudoperoxidase activity of hemoglobin.

Guaiac acid impregnated in filter paper, stool applied to one side, and peroxidase reagent is added to the other side. Observe for blue colour –> Positive. Patient will need further testing (i.e. colonoscopy, etc.).

No blue colour –> Negative