Proteins and Tumor Markers

Question 1

Total protein reference range:

Albumin reference range:

Answer 1

TP = 6.5-8.3 g/dL
Albumin = 3.5-5.0 g/dL

Question 2

Prealbumin (transthyretin)

Answer 2

Indicates nutritional status, transports thyroid hormones
Decreased: liver disorder, inflammation, malignancy, poor nutrition
Increased: steroids, renal failure, alcoholism

Question 3

Albumin

Answer 3

Highest conc. of all plasma proteins
Transports many things, significantly contributes to osmotic pressure
Decreased: liver disorders, GI malabsorption, muscle-wasting diseases, burns, renal disease, starvation/nutrition
Increased: dehydration

Question 4

alpha1-Antitrypsin

Answer 4

Neutralizes trypsin-type enzymes
Decreased: emphysema related pulmonary disease, juvenile hepatic disorders
Increased: inflammatory disorders

Question 5

alpha1-Fetoprotein

Answer 5

Synthesized in gestation, peak at 13 weeks and decline at 34 weeks
Increased: neural tube defects, spina bifida, fetal distress
Decreased: Down syndrome, trisomy 18

In adults, increased: hepatocellular carcinoma and gonadal tumors

Question 6

alpha1-Acid glycoprotein (orosomucoid)

Answer 6

Binds to basic drugs
Increased: inflammatory, RA, pneumonia, conditions with cell proliferation
Decreased: nephrotic syndrome

Question 7

Haptoglobin

Answer 7

Binds free hemoglobin
Increased: inflammatory, burns, trauma
Decreased: intravascular hemolysis (liver removes haptoglobin-hemoglobin complex)

Question 8

Ceruloplasmin

Answer 8

Binds copper
Increased: pregnancy, inflammatory, malignancy, oral estrogen/contraceptives
Decreased: Wilson disease, malnutrition, liver disease

Question 9

alpha2-Macroglobulin

Answer 9

Inhibits thrombin, trypsin, and pepsin
Increased: nephrotic syndrome, contraceptives, pregnancy, estrogen therapy
Decreased: acute inflammatory disorders, prostatic cancer, acute pancreatitis

Question 10

Transferrin

Answer 10

Transports iron
Decreased: infections, liver disease, nephrotic syndrome
Increased: iron-deficiency anemia, pregnancy

Question 11

C-reactive protein

Answer 11

Increased: tissue necrosis, rheumatic fever, infections, MI, RA, gout
< 1 mg/L = low risk
1-3 mg/L = average risk
> 3 mg/L = high risk

Question 12

IgG

Answer 12

Can cross placenta
Increased: liver disorders, infection, collagen disease
Decreased: increased susceptibility to infection

Question 13

IgA

Answer 13

Increases after birth
Increased: liver disorders, infections, autoimmune diseases
Decreased: inhibited protein synthesis, hereditary immune disorders

Question 14

IgM

Answer 14

Made by fetus
Increased: bacterial/viral/fungal infections, Waldenstrom macroglobulinemia
Decreased: protein loss in renal disorders, immunodeficiency disorders

Question 15

IgD

Answer 15

Increased in liver disorders, infection, and connective tissue disorders

Question 16

IgE

Answer 16

Increased in allergies, asthma, hay fever, parasitic infections

Question 17

Fetal fibronectin

Answer 17

Predict risk of premature birth (leakage from placenta into cervicovaginal secretions

Question 18

Biuret method

Answer 18

Cupric ions bind to peptide bonds, produce purple complex, amount of purple directly proportional to amount of protein

Question 19

Kjeldahl method

Answer 19

Quantify nitrogen content of protein

Question 20

Albumin dye binding

Answer 20

Use bromcresol green and bromcresol purple

Question 21

Calculation for globulins

Answer 21

Total protein - albumin = globulins

Question 22

Urine protein

Answer 22

Test with sulfosalicylic acid, trichloroacetic acid, benzethonium chloride, and Coomassie brilliant blue
Ref. range = 1-14 mg/dL, < 100 mg/day
Increased: multiple myeloma, nephrotic syndrome, tubular/glomerular dysfunction

Question 23

CSF protein

Answer 23

Test with sulfosalicylic acid, trichloroacetic acid, benzethonium chloride, and Coomassie brilliant blue
Ref. range = 15-45 mg/dL
Increased: meningitis, traumatic tap, MS, herniated disk, cerebral infarction
Decreased: hyperthyroidism, CNS leakage of CSF

Question 24

Prostate-specific antigen (PSA)

Answer 24

Produced in prostate, function in liquefaction of seminal coagulum
Tissue specific but not tumor specific
PSA > 2.5 ng/mL = perform biopsy
Men with prostate cancer tend to have low free % PSA compared to benign disease

Question 25

Carcinoembryonic antigen (CEA)

Answer 25

Found in fetal GI tract

Increased: adenocarcinoma of digestive tract, colorectal cancer

Question 26

Human chorionic gonadotropin (hCG)

Answer 26

Beta subunit unique so it’s tested for

Increased: trophoblastic tumors, choriocarcinoma, nonseminomatous testicular tumor, ovarian tumor

Question 27

CA 15-3

Answer 27

Monitoring therapeutic response and recurrence of breast cancer
Increased: chronic hepatitis, TB, systemic lupus erythrmatosus

Question 28

CA 125

Answer 28

Ovarian and endometrial cancer

Question 29

CA 19-9

Answer 29

Derived from Lewis blood group

Marker for pancreatic, colorectal, lung, and gastric carcinomas

Question 30

Serum protein electrophoresis at pH 8.6, protein order from left to right

Answer 30

Albumin, alpha-1 globulin, alpha-2 globulin, beta globulin, gamma globulin