Tumor Markers Flashcards
(31 cards)
Hook Effect - A very ___ concentration of an analyte gives a falsely ___ result
-Very high concentration of an analyte gives a falsely LOW result
What is the mechanism of the Hook Effect?
-How can this be overcome
High concentration exceeds the binding capacity of both the binding capture antibodies and the signal bearing antibodies, preventing their association.
*If the sample is sufficiently diluted, the assay will give an appropriate result
What are considered indications for prostate needle biopsy?
-PSA >4 ng/mL
or
-Abnormal DRE
(controversial)
What percentage of men with elevated PSA (>4 ng/mL), have prostate cancer?
30-40%
What is true regarding PSA and race?
Levels are significantly higher in Blacks
T/F: Many men with prostate cancer have serum PSA <4.0 ng/mL.
True
-Poor Sensitivity
Fecal occult blood testing:
-Guaiac blood testing mechanism
Hemoglobin has endogenous peroxidase activity that is capable of oxidizing guaiac in the presence of hydrogen peroxide to a blue colored product.
Fecal occult blood testing - Guaiac blood testing:
- False-Positives
- False-Negatives
False Positives:
- NSAID use
- Consumption of heme (Meat)
- Consumption of peroxidase (turnips,horseradish)
Carcinoembryonic Antigen (CEA): -High preoperative CEA
Worse overall outcome
CEA may be elevated in what cancers? (8)
- GI
- Gastric
- Breast
- Pancreatic
- Lung
- Medullary Thyroid
- Cervical Adenoca
- Urothelial
What neoplasms are associated with elevated (cancer antigen) CA-125?
Nonmucinous Epithelial Ovarian neoplasms
CA27.29 (aka BR27.29) and CA15-3:
- protein product of what gene?
- Elevated in what?
- MUC1 gene
- Advanced stage breast cancer (both elevated in 60-70%)
What is the marker for pancreatic adenocarcinoma; elevated in 80% at presentation?
CA19-9
Who does not produce CA19-9?
Lewis negative patients
Where is alpha-fetoprotein (AFP) normally synthesized? (3)
- Yolk sac
- Fetal Liver
- Fetal GI tract
What NONneoplastic conditions are associated with an elevated AFP? (3)
- Pregnancy (normal)
- Cirrhosis
- Hepatitis
What neoplastic conditions are associated with an elevated AFP? (2)
- Yolk Sac tumors
- Hepatocellular Carcinomas (Most)
What conditions are associated with an elevated Human Chorionic Gonadotropin (HCG)? (4)
- Preganancy
- Gestational Trophoblastic Disease
- Choriocarcinoma
- Dysgerminoma/Seminoma (15%)
What tumor marker is elevated whenever there is increased cell death?
beta2-microglobulin
B2-microglobulin is an independent prognostic factor in what?
Multiple Myeloma
Alkaline Phosphatase:
- Indication of what?
- Elevated in what conditions
- Sensitive test for what?
- Osteoblastic activity
- Osteogenic Sarcoma or Bone Mets
- Sensitive test for Hepatic Metastases
What do carcinoids produce (generally)?
-Metabolite that is excreted into urine
Serotonin (5-HT)
-5-Hydroxyindoleacetic acid (5-HIAA)
GI Carcinoids produce?
- Foregut (3)
- Midigut (1)
- Hindgut (1)
Foregut
- Histamine
- Catecholamines
- 5-Hydroxytryptamine (5-HTP)
Midigut
-Serotonin (5-HT)
Hindgut
-Nonsecretory
Markers for Medullary Thyroid Carcinoma (2).
- Calcitonin
- CEA
