Proteins and Tumor Markers

  1. What are tumor markers used for?
    • Tumor staging
    • (not very useful in diagnosis)
  2. Name the ideal characteristics of a tumor marker
    • Measured easily
    • High analytical sensitivity of assay method
    • High analytical specificity of assay method
    • Cost effective
    • Test result contribute to patient care and outcome
  3. Where is the prostate specific antigen (PSA)?
    Produced by the epithelial cells of the prostate gland
  4. What form of PSA in the blood would lack immunoreactivity?
    PSA enveloped by protease inhibitor, alpha2-macroglobulin
  5. What form of PSA found in the blood is immunologically detectable - but complexed?
    Complexed to another protease inhibitor, alpha1-antichymotrypsin
  6. What form of PSA found in blood is immunogically detectable - but free?
    Free PSA is NOT complexed to a protease inhibitor
  7. Describe the specificity of PSA
    • PSA is a tissue specific marker but NOT tumor specific
    • Small amounts are present in the serum normally
    • Lacks specificity because serum PSA is increased in benign protstate hypertrophy as well as in adenocarcinoma of the prostate
  8. When is a biopsy of the prostate recommended?
    • PSA >2.5 ng/mL
    • or
    • Rise in PSA >0.75 ng/mL/year - even if <2.5 ng/mL
  9. What PSA test is associated with a higher risk of prostate cancer?
    Lower % Free PSA is associated with higher risk of prostate cancer
  10. What mehodologies are used to measure PSA?
    • Fluorescence immunoassay
    • Enzyme immunoassay
    • Chemiluminescence immunoassay
  11. What tumor marker is the oncofetal glycoprotein antigen and synthesized in the liver, yolk sac, and GI tract of the fetus?
    alpha1-Fetoprotein (AFP)
  12. What is the reference range of AFP?
    Adult <20 ng/mL
  13. What causes an increase in AFP, in a nonpregnant person?
    • Hepatocellular carcinoma
    • Testicular and ovarian teratocarcinomas
    • Pancreatic carcinoma
    • Gastric and colonic carcinomas
    • Nonmalignant disorders (Hepatitis and Chronic active hepatitis)
  14. What is AFP also used for, other than a tumor marker?
    To monitor therapeutic response of cancer patients to treatment protocols
  15. What causes AFP to increase in a pregnant person?
    • Spina bifida
    • Neural tube defects
    • Fetal distress
  16. What causes AFP to decrease in a pregnant person?
    Down syndrome
  17. What tumor marker is an oncofetal glycoprotein antigen and normally found in epithelial cells of the fetal GI tract?
    Carcinoembryonic antigen (CEA)
  18. What causes an increase in CEA?
    • Adenocarcinoma of digestive tract
    • Colorectal carcinoma
    • Other malignancies
    • Noncancerous disorders
  19. What is CEA also used for, other than a tumor marker?
    Monitoring therapeutic response of cancer patients to treatment protocols
  20. What tumor markers can also be used to monitor therapeutic response of cancer patients to treatment protocols?
    • AFP
    • CEA
  21. What tumor marker is a glycoprotein that is composed of alpha and beta-subunits?
    hCG (human chorionic gonadotropin)
  22. What normally secretes hCG?
    Trophoblast cells of the placenta
  23. What subunit is unique to hCG?
    Beta subunit
  24. What causes an increase in hCG?
    • Trophoblastic tumors
    • Choriocarcinoma
    • Nonseminomatous testicular tumors
    • Ovarian tumors
  25. What tumor marker is a mucin glycoprotein antigen and useful for monitoring therapeutic response and detecting recurrence of breast cancer in patients previously treated?
    CA 15-3
  26. What causes an increase in CA 15-3?
    • Chronic hepatitis
    • Tuberculosis
    • Systemic lupus erythematosus
  27. What tumor marker is a mucin glycoprotein antigen and a marker for ovarian and endometrial cancer?
    CA 125
  28. What tumor marker is a glycolipid blood group antigen-related marker, a derivative of the Lewis blood group Lexa, and a marker for pancreatic, colorectal, lung, and gastric carcinomas?
    CA 19-9
  29. Name the test methods used for quantification of 24 hour urinary protein
    • Turbidimetric
    • Spectrophotometric
  30. What is the reference range for urine total protein (random and 24 hour)?
    • Random - 1-14 mg/dL
    • 24 Hour - <100 mg/day
  31. What causes an increase in urine protein?
    • Tubular or glomerular dysfunction
    • Multiple Myeloma
    • Waldenstrom macroglobulinemia
    • Nephrotic syndrome
  32. What protein may be found in the urine of patients with multiple myeloma?
    Bence Jones protein
  33. What can cause the glomerular membrane to be damaged?
    • Diabetes
    • Amyloidosis
    • Collagen disease
  34. Glomerular dysfunction can be detected in its early stages by measuring what in the urine?
  35. What is a condition where the quantity of albumin in the urine is greater than normal, yet it is not able to be detected by the urine dipstick method?
  36. The presence of microalbumin in a diabetic individual is a concern because it ___________
    Generally precedes nephropathy
  37. What are the methods for the quantification of microalbumin?
    • Enzyme immunoassays
    • Immunonephelometric assays
  38. What is the reference range of urine albumin?
    <30 mg/day
  39. What is CSF and where is it formed?
    • Ultrafiltrate of plasma
    • Formed in the ventricles of the brain
  40. Name the test methods used for CSF
    • Turbimetric
    • Spectrophotometric
  41. What is the reference range for CSF protein?
    15-45 mg/dL
  42. What causes an increase in CSF protein?
    • Viral, bacterial, and fungal meningitis
    • Traumatic tap
    • Multiple sclerosis
    • Herniated disk
    • Cerebral infarction
  43. What causes a decrease in CSF protein?
    • Hyperthyroidism
    • CNS leakage of CSF
  44. What methodology is based on the change in velocity of light (light is bent) as light passes through the boundary between air and water, which function as 2 transparent layers?
  45. What methodology is based on curpic ions complexing with peptide bonds in an alkaline medium to produce a purple-colored complex?
    Biuret method
  46. What methodology is a technique that allows proteins to bind to a dye, forming a protein-dye complex that results in a shift of the maximum absorbance of the dye?
    Dye binding techniques
  47. What reagent is generally used in dye binding techniques?
    Coomassie brilliant blue
  48. What technique is used for the determination of total protein but is considered too cumbersom for use in routine testing - it is considered the reference method of choice to validate the biuret method?
    Kjedahl technique
  49. What electrophoresis is a type of zone electrophoresis in which protein separation is based on the isoelectric point (pI)?
    Isoelectric focusing
  50. Name the Immunochemical methods
    • Homogeneous and heterogeneous immunoassays
    • Immunonephelometry
    • Immunoelectrophoresis
    • Radial immunodiffusion (RID)
    • Electroimmunodiffusion
    • Immunofixation
  51. What is the test methodology for albumin?
    Dye binding techniques using bromcresol green and broncresol purple dyes allow albumin to be positively charged for binding to the anionic dye, forming an albumin-dye complex that results in a shift of the maximum absorbance of the dye
  52. What is the test methodology for globulins?
    • Calculation
    • Globulins = Total Protein - Albumin
  53. What is the calculation for globulins?
    Globulins = Total Protein - Albumin
Card Set
Proteins and Tumor Markers
Tumor Marker Utilization, Protien in Body fluids, Methodology