Webster's New World Medical Dictionary

tumor, sweat gland
See 
syringoma.
tumor debulking
Surgically removing as much
of a tumor as possible.
tumor marker
A substance that can be detected
in higher-than-normal amounts in the blood, urine,
or body tissues of some patients with certain types
of cancer. A tumor marker may be made by a tumor
itself, or it may be made by the body as a response
to the tumor. Tumor marker tests are not used alone
to detect and diagnose cancer because most tumor
markers can be elevated in patients who don’t have
a tumor, because no tumor marker is entirely spe-
cific to a particular type of cancer, and because not
every cancer patient has an elevated tumor marker
level, especially in the early stages of cancer, when
tumor marker levels are usually still normal.
Although tumor markers are typically imperfect as
screening tests to detect occult (hidden) cancers,
when a particular tumor has been found with a
marker, the marker can be a means of monitoring
the success or failure of treatment. The tumor
marker level may also reflect the extent (stage) of
the disease, indicate how quickly the cancer is likely
to progress, and help determine the outlook.
Examples of tumor markers include alpha-fetopro-
tein (AFP), carcinoembryonic antigen (CEA),
human chorionic gonadotropin (HCG), lactate
dehydrogenase (LDH), prostate specific antigen
(PSA), and neuron-specific enolase (NSE).
tumor marker, CEA
See 
carcinoembryonic
antigen.
tumor marker, NSE
See 
neuron-specific eno-
lase test.
tumor necrosis factor
One of multiple proteins
capable of inducing necrosis (death) of tumor cells
that possess a wide range of proinflammatory
actions. Abbreviated TNF. TNF is a multifunctional
cytokine with effects on lipid metabolism, coagula-
tion, insulin resistance, and the function of endothe-
lial cells lining blood vessels. Drugs that block the
action of TNF have been shown to be beneficial in
reducing the inflammation in inflammatory diseases
such as Crohn’s disease and rheumatoid arthritis.
tumor registry
Recorded information about the
status of patients with tumors. Although a registry
was originally the place where information was col-
lected (in registers), the word registry has also
come to mean the collection itself. A tumor registry
is organized so that the data can be analyzed. For
example, analysis of data in a tumor registry main-
tained at a hospital may show a rise in lung cancer
among women.