Tumor Markers Flashcards

1
Q

What produces tumor markers?

A

The tumor itself or as an effect of tumor on healthy host tissue

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2
Q

What are tumor markers used for?

A
Screening
Diagnosis
Prognosis
Monitor therapy
Detect recurrence
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3
Q

T/F: Most tumor markers are also present in normal, healthy tissue or benign conditions

A

True

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4
Q

T/F Specific quantity of a TM is more important than the rate of increase in determining a patient’s prognosis

A

False. Rate of increase (velocity) is more important.

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5
Q

Highest levels of TM seen when tumor _______

A

metastasizes

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6
Q

3 things that make a good tumor marker

A
  1. Specific
  2. Absent in normal population
  3. Readily detectable
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7
Q

4 categories of commonly used tumor markers

A
  1. Enzymes
  2. Proteins
  3. Hormones/hormone metabolites
  4. Oncofetal antigens
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8
Q

Why is measuring B-2 microglobulin useful?

A

It’s found on the surface of nucleated cells. Measures cell turnover.
Used to monitor renal transplant patients for rejection.

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9
Q

How do we detect tumor makers?

A

Quantitative immunoassay

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10
Q

What is the hook effect?

A

What happens when analyte exceeds analytical range. Labeled antibodies are saturated and a “sandwich” is not formed. This causes a reduction in signal as the concentration increases. The line plotted is curved, not linear.

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11
Q

How do we compensate for the hook effect?

A

Dilute the sample

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12
Q

What may interfere with TM detection/measurement?

A

Icterus, lipemia, hemolysis
Cross-reacting antibodies
Carry-over (from reusable probe, etc.)

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13
Q

What is alpha-fetoprotein measurement used for?

A

Diagnosis and prognosis of hepatocellular carcinoma

Also seen in germ cell tumors

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14
Q

AFP with beta-HCG can be used to classify & stage _______ cancer

A

testicular

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15
Q

Is AFP completely specific?

A

No- increases seen in pregnancy, liver disease

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16
Q

What level of AFP is diagnostic of HHC in high-risk patients?

A

> 500 ng/mL (The higher, the worse)

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17
Q

AFP is usually synthesized by the _____ _______

A

fetal liver

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18
Q

What is CEA (carcinoembryonic antigen) used to detect?

A

Relapse of colorectal cancer (after diagnosis has been made)

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19
Q

Is CEA useful as a screening test for colorectal cancer?

A

No- it is not tumor-specific; may be elevated in other conditions

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20
Q

HCG is normally secreted by cells of _______ to prepare and maintain pregnancy

A

placenta

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21
Q

How is HCG used as a tumor marker?

A

Prognostic indicator of ovarian cancer
Diagnostic marker to classify testicular disease
Helps detect Gestational trophoblastic disease

22
Q

Prostate specific antigen (PSA) is only produced by…

A

epithelial cells of prostatic ducts in prostate

23
Q

What is PSA best used for?

A

Monitoring the progression of prostate cancer after therapy

24
Q

Why would we measure both total and free PSA?

A

Total PSA (measures free & complexed PSA): screen for & monitor prostate cancer

Free PSA: patients with malignancy may have lower free PSA

25
Q

T/F Prostate cancer may be present at normal PSA concentration

A

True

26
Q

What is CA-125 used to detect?

A

Ovarian cancer

27
Q

Is CA-125 used to screen asymptomatic patients?

A

No. Although it may be used to screen high-risk patients (family Hx or prior Hx of ovarian cancer)

28
Q

T/F CA-125 levels do not correlate with stage of cancer

A

False- they do correlate

29
Q

CA-125 is only clinically accepted marker for ______ _______

A

Ovarian cancer

30
Q

Can CA-125 be used to distinguish ovarian cancer from benign masses?

A

yes- benign masses don’t secrete this tumor marker

31
Q

What is CA 19-9 used for?

A

To differentiate between pancreatic cancer and other cancers

Monitor treatment & recurrence

32
Q

High levels of CA 19-9 correlate with…..

A

disease progression, outcomes

33
Q

Is CA 19-9 useful as a screening tool?

A

No

34
Q

What is CA 15-3 used for?

A

Monitoring breast cancer treatment and disease recurrence

35
Q

Can 15-3 be used alone to come to a diagnosis?

A

No- needs to be combined with history, physical exam, imaging

36
Q

Why are 19-9 and 15-3 not useful as screening tests?

A

Levels may be increased in other benign or malignant conditions. May also be up in healthy individuals.

37
Q

How can an elevated CK level from cancer be differentiated from elevation due to MI?

A

MI will cause CK to increase and then decrease.

In cancer, CK will increase and remain elevated

38
Q

What are useful protein markers?

What makes a good marker?

A

Albumin, transferrin, prealbumin

Short half-life makes a better marker

39
Q

If transport protein levels are decreased, how can we tell if this is from inflammation or malnutrition?

A

CRP- high in inflammatory conditions

40
Q

T/F: Albumin levels can classify severity of malnutrition

A

True

41
Q

Definition of Kwashiorkor

A

Chronic protein deficiency with adequate non-protein intake.

42
Q

S/S of Kwashiorkor

A

low albumin, edema, hepatomegaly

43
Q

Definition of Marasmus

A

Deficiency of calories with adequate protein intake

44
Q

S/S of Marasmus

A

Severe reduction in body weight (thin with wasting muscles), normal albumin levels, edema is rare

45
Q

Why is transferrin a better marker of protein depletion than albumin?

A

Shorter half-life

46
Q

Transferrin in synthesized by the _________. It binds and transports _____ _______.

A

liver

ferric iron

47
Q

Increased transferrin levels can indicate iron ________

A

deficiency.

48
Q

Can transferrin be used to diagnose malnutrition?

A

Maybe

49
Q

What are the main roles of pre-albumin?

A

Transport thyroxin and Vitamin A

50
Q

What do levels of Pre-albumin <80 mg/dL indicate?

A

severe protein-calorie malnutrition

51
Q

Pre-albumin levels can also be used to monitor _____ in diabetic patients with ulcers or post-op patients

A

healing

52
Q

What is another name for pre-albumin?

A

Transthyretin