Tumour markers are substances that can often be detected in higher-than-normal amounts
in the blood, urine, or body tissues of some patients with certain types of cancer.
Tumour markers are produced either by the tumour itself or by the body in response
to the presence of cancer.
Currently, the main use of tumour markers is to assess a cancer's response to treatment
and to check for recurrence. Scientists continue to study these uses of tumour markers
as well as their potential role in the early detection and diagnosis of cancer.
Described below are some of the most commonly measured tumour markers
CA 125:is produced by
a variety of cells, but particularly by ovarian cancer cells and is used primarily
in the management of ovarian cancer. In women receiving chemotherapy, a falling
CA 125 level generally indicates that the cancer is responding to treatment. Increasing
CA 125 levels during or after treatment, on the other hand, may suggest that the
cancer is not responding to therapy or residual cancer cells are present in the
body. CA 125 levels is used to monitor patients for recurrence of ovarian cancer.
Not all women with elevated CA 125 levels have ovarian cancer. CA 125 levels may
also be elevated by cancers of the uterus, cervix, pancreas, liver, colon, breast,
lung, and digestive tract. Benign conditions that can cause elevated CA 125 levels
include endometriosis, pelvic inflammatory disease, peritonitis, pancreatitis, liver
disease, and any condition that inflames the pleura. Menstruation and pregnancy
can also cause an increase in CA 125.
Carcinoembryonic antigen (CEA):-
is normally found in small amounts in the blood of most healthy people,
but may be elevated in cancer or some benign conditions. CEA is used in monitoring
colorectal cancer, especially when the disease has metastasized or recurred. However,
a wide variety of other cancers including melanoma; lymphoma; and cancers of the
breast, lung, pancreas, stomach, cervix, bladder, kidney, thyroid, liver, and ovary
may lead to elevated CEA levels. Benign conditions such as inflammatory bowel disease,
pancreatitis and liver disease, tobacco use can also contribute to higher levels
is normally produced by a developing fetus. AFP levels begin to decrease soon after
birth and are usually undetectable in the blood of healthy adults (except during
pregnancy). An elevated level of AFP strongly suggests the presence of either primary
liver cancer or germ cell cancer (cancer that begins in the cells that give rise
to eggs or sperm) of the ovary or testicle. Only rarely do patients with other types
of cancer (such as stomach cancer) have elevated levels of AFP. Benign conditions
that can cause elevated AFP levels include benign liver conditions, such as cirrhosis
or hepatitis; ataxia telangiectasia; Wiscott-Aldrich syndrome; and pregnancy.
Human chorionic gonadotropin (HCG):-
is normally produced by the placenta during pregnancy. In fact, HCG is
sometimes used as a pregnancy test because it increases early within the first trimester.
It is also used to screen for choriocarcinoma (a rare cancer of the uterus) in women
who are at high risk for the disease, and to monitor the treatment of trophoblastic
disease (a rare cancer that develops from an abnormally fertilized egg). Elevated
HCG levels may also indicate the presence of cancers of the testis, ovary, liver,
stomach, pancreas, and lung. Pregnancy and marijuana use can also cause elevated
CA 19-9:- Initially found
in colorectal cancer patients, CA 19-9 has also been identified in patients with
pancreatic, stomach, and bile duct cancer. Higher levels of CA 19-9 tend to be associated
with more advanced cancer of pancreas. Benign conditions that may elevate CA 19-9
levels include gallstones, pancreatitis, cirrhosis of the liver, and cholecystitis.
CA 15-3:-levels are most
useful in following the course of treatment in women diagnosed with breast cancer,
especially advanced breast cancer. CA 15-3 levels are rarely elevated in women with
early stage breast cancer. Cancers of the ovary, lung, and prostate may also raise
CA 15-3 levels. Elevated levels of CA 15-3 may be associated with benign conditions,
such as benign breast or ovarian disease, endometriosis, pelvic inflammatory disease,
and hepatitis. Pregnancy and lactation can also cause CA 15-3 levels to rise.
CA 27-29:-. Similar
to the CA 15-3 antigen, CA 27-29 is found in the blood of most breast cancer patients.
CA 27-29 levels may be used in conjunction with other procedures (such as mammograms
and measurements of other tumour marker levels) to check for recurrence in women
previously treated for stage II and stage III breast cancer. CA 27-29 levels can
also be elevated in cancers of the colon, stomach, kidney, lung, ovary, pancreas,
uterus, and liver. First trimester pregnancy, endometriosis, ovarian cysts, benign
breast disease, kidney disease, and liver disease are noncancerous conditions that
can also elevate CA 27-29 levels.