Tumor Marker:- Part 13 – ACTH, Calcitonin, HCG
Adrenocorticotropic hormone(ACTH)
- This is a polypeptide hormone produced by the corticotropic cells of the anterior pituitary gland.
- ACTH is a tropic hormone, it binds to the cells of the adrenal cortex and influences their activities.
- ACTH in plasma is highest between 6 to 8 AM and lowest in the evening between 6 to 11 PM.
- ACTH may be raised as primary or ectopic production.
- Ectopic production from:
- Small cell carcinoma of the lung ( >200 ng/L).
- Pancreatic carcinoma.
- Breast.
- Stomach.
- Colon.
- Benign conditions are:
- Chronic obstructive pulmonary disease.
- Mental depression.
- Obesity.
- Hypertension.
- Diabetes.
- Stress.
- ACTH in normal person does not exceed 50 pg/mL at its peak and the basal level is near 5 pg/mL.
- Raised ACTH level is seen in:
- In primary adrenal deficiency.
- In patients with Cushing’s syndrome.
- In patients with ectopic tumors e.g.
- Basophilic neoplasm of the anterior pituitary.
- Ectopic carcinoma of the lung.
- Normal
- AM level = <80 pg/mL (<18 pmol/L).
- PM level = <50 pg/mL (<11 pmol/L).
Human Chorionic gonadotropin hormone (HCG)
- This is also called Chorionic gonadotropin.
- This is a glycoprotein secreted by the syncytiotrophoblastic cells of the placenta.
- This consists of two subunits:
- α- HCG.
- β-HCG.
- This consists of two subunits:
- Elevated HCG level is seen in:
- Trophoblastic disease (level is usually >one million IU/L).
- Germ cell tumor and non-seminomatous tumors of the testis (there is a moderate increase).
- Reported in melanoma and carcinoma of the breast, GIT tumors, lung, and ovary.
- The presence of HCG in seminoma indicates another component as choriocarcinoma.
- Also raised in benign conditions like:
- Cirrhosis.
- Duodenal ulcer.
- Inflammatory bowel diseases.
- Pregnancy.
- Normal HCG
- Male and nonpregnant females = <5 mIU/mL.
Calcitonin
- This is a polypeptide with 32 amino acids.
- This is produced by the C cells of the thyroid.
- The serum half-life is 12 minutes.
- In a normal person is <0.1 µg /L.
- This is produced in response to increased serum calcium levels.
- Calcitonin is useful for the monitoring of disease after treatment.
- It inhibits the release of calcium from the bone, lowers the serum calcium.
- Calcitonin is useful to diagnose :
- Medullary carcinoma of the thyroid.
- Carcinoid tumor.
- Lung cancers.
- Breast cancer.
- Kidney tumor.
- Liver tumor.
- Calcitonin level also raised in nonmalignant conditions like:
- Pulmonary disease.
- Pancreatitis.
- Hyperparathyroidism.
- Paget’s disease of bone.
- Pregnancy.
- Pernicious anemia.
- Normal (Source 2)
- Basal (plasma)
- Male = ≤19 pg/mL (≤19 ng/L)
- Female = ≤14 pg/mL (≤14 ng/L)
- Calcium infusion (2.4 mg/kg)
- Male = ≤190 pg/mL (≤190 ng/L)
- Femal = ≤130 pg/mL (≤130 ng/L)
- Pentagastrin injection (0.5 µg/kg)
- Male = ≤110 pg/mL (≤110 ng/L)
- Female = ≤30 pg/mL (≤30 ng/L)
- Basal (plasma)