Tumor Marker:- Part 13 – ACTH, Calcitonin, HCG

Adrenocorticotropic hormone(ACTH)

1. This is a polypeptide hormone produced by the corticotropic cells of the anterior pituitary gland.
   1. ACTH is a tropic hormone, it binds to the cells of the adrenal cortex and influences their activities.
   2. ACTH in plasma is highest between 6 to 8 AM and lowest in the evening between 6 to 11 PM.

2.  ACTH may be raised as primary or ectopic production.
3. Ectopic production from:
   1. Small cell carcinoma of the lung ( >200 ng/L).
   2. Pancreatic carcinoma.
   3. Breast.
   4. Stomach.
   5. Colon.
4. Benign conditions are:
   1. Chronic obstructive pulmonary disease.
   2. Mental depression.
   3. Obesity.
   4. Hypertension.
   5. Diabetes.
   6. Stress.
5. ACTH in normal person does not exceed 50 pg/mL at its peak and the basal level is near 5 pg/mL.
6. Raised ACTH level is seen in:
   1. In primary adrenal deficiency.
   2. In patients with Cushing’s syndrome.
   3. In patients with ectopic tumors e.g.
      1. Basophilic neoplasm of the anterior pituitary.
      2. Ectopic carcinoma of the lung.
7. Normal
   1. AM level = <80 pg/mL (<18 pmol/L).
   2. PM level = <50 pg/mL (<11 pmol/L).

Human Chorionic gonadotropin hormone (HCG)

1. This is also called Chorionic gonadotropin.
2. This is a glycoprotein secreted by the syncytiotrophoblastic cells of the placenta.
   1. This consists of two subunits:
      1. α- HCG.
      2. β-HCG.
3. Elevated HCG level is seen in:
   1. Trophoblastic disease (level is usually >one million IU/L).
   2. Germ cell tumor and non-seminomatous tumors of the testis (there is a moderate increase).
   3. Reported in melanoma and carcinoma of the breast, GIT tumors, lung, and ovary.
4. The presence of HCG in seminoma indicates another component as choriocarcinoma.
5. Also raised in benign conditions like:
   1. Cirrhosis.
   2. Duodenal ulcer.
   3. Inflammatory bowel diseases.
   4. Pregnancy.
6. Normal HCG
   1. Male and nonpregnant females = <5 mIU/mL.

Calcitonin

1. This is a polypeptide with 32 amino acids.
   1. This is produced by the C cells of the thyroid.
   2. The serum half-life is 12 minutes.
   3. In a normal person is <0.1 µg /L.
2. This is produced in response to increased serum calcium levels.
3. Calcitonin is useful for the monitoring of disease after treatment.
4. It inhibits the release of calcium from the bone, lowers the serum calcium.
5. Calcitonin is useful to diagnose :
   1. Medullary carcinoma of the thyroid.
   2. Carcinoid tumor.
   3. Lung cancers.
   4. Breast cancer.
   5. Kidney tumor.
   6. Liver tumor.
6. Calcitonin level also raised in nonmalignant conditions like:
   1. Pulmonary disease.
   2. Pancreatitis.
   3. Hyperparathyroidism.
   4. Paget’s disease of bone.
   5. Pregnancy.
   6. Pernicious anemia.
7. Normal (Source 2)
   1. Basal (plasma)
      1. Male = ≤19 pg/mL  (≤19 ng/L)
      2. Female = ≤14 pg/mL  (≤14 ng/L)
   2. Calcium infusion  (2.4 mg/kg)
      1. Male = ≤190 pg/mL  (≤190 ng/L)
      2. Femal =   ≤130 pg/mL  (≤130 ng/L)
   3. Pentagastrin injection (0.5 µg/kg)
      1. Male = ≤110 pg/mL  (≤110 ng/L)
      2. Female = ≤30 pg/mL   (≤30 ng/L)

---