As mentioned earlier, cancer cells produce large quantity of proteins, enzymes
and in some cases hormones. The elevated levels may he used to detect, monitor
the progress of therapy and prognose the outcome of the disease. These abnormal
substances are called tumor markers. They are quite specific and therefore can
be used to differentiate or identify the type of cancer.
Whilst positive results of such tests are strong indications of cancer, the same
cannot be said for a negative reading.
Other diagnostic procedures are necessary for suspected cases.
Information extracted from the manufacturer’s brochure
a. CEA (Carcinoma‑Embryonic Antigen)
CEA is a glycoprotein present on the cell surface and normally found in
embryonic and fetal gut tissues.
CEA is used as a marker for colorectal cancer and cancer of the lung, breast and
pancreas.
b. AFP (Alpha‑Fetoprotein)
AFP is a fetal serum glycoprotein. It is synthesized in the liver and the
developing fetal gastro‑intestinal tract. Elevated levels of AFP have been found
in patients with hepato-cellular carcinoma and in pregnancy.
c. Calcitonin
This is a peptide hormone produced by the thyroid gland. This marker is used for
the diagnosis and monitoring of medullary cancer of the thyroid.
d. PAP (Prostate Acid Phosphatase)
This is a glycoprotein secreted by the prostate gland. Serum levels in patients
have been shown to increase proportionately as the stage of prostate cancer
progresses. Non-cancerous prostate conditions such as benign prostatic
hypertrophy and prostatitis may also cause elevations.
It is a useful marker for detecting, monitoring and prognosing prostate cancer.
e. PSA (Prostate‑Specific Antigen)
This is another glycoprotein secreted by the prostate gland. Elevated levels of
this protein in the blood have been found in prostate cancer, benign prostatic
hypertrophy and prostatitis.
PSA is a useful marker for monitoring the progress of treatment often in
conjunction with PAP) in patients with prostate cancer.
f. CA 125 (Cancer Antigen 125)
This is a glycoprotein present on the cell surface of ovarian tissue. This
protein is absent in normal adult ovarion cells. However, increased levels are
found during menstruation and pregnancy. Abnormally high levels occur in
approximately 75% of ovarion cancer patients and tend to correlate with tumor
size and recurrence.
g. CA 19-9 (Carbohydrate Antigen 19-9)
This is a glycoprotein found on the surface of cancer cells. Patients with
advanced colorectal, gastric or pancreatic cancers may exhibit elevated CA 19-9
values in serum.
h. hCG (Human Chorionic Gonadotropin)
This is a glycoprotein secreted by normal placental cells. Elevated levels have
been reported in patients with trophoblastic or germ cell tumors, breast cancer,
choriocarcinoma and testicular carcinoma.