AMERICAN ASSOCIATION FOR CANCER RESEARCH 129
from a machine outside the body (external-beam radiation
therapy), or it may come from radioactive material placed
in the body near cancer cells (internal radiation therapy).
Systemic radiotherapy uses a radioactive substance, such
as a radiolabeled monoclonal antibody, that travels in
the blood to tissues throughout the body. Also called
irradiation and radiation therapy.
Receptor A protein in a cell that attaches to specific
molecules, such as hormones, from outside the cell, in a
lock-and-key manner, producing a specific effect on the
cell—for example, initiating cell proliferation. Receptors
are most commonly found spanning the membrane
surrounding a cell but can be located within cells.
Renal cell carcinoma The most common form of kidney
cancer diagnosed in U.S. adults. It begins in cells that line
the tubules of the kidney, which is where blood is filtered
Signaling pathway/signaling network A group of
molecules in a cell that work together to control one or
more cell functions, such as cell proliferation or cell death.
After the first molecule in a pathway receives a signal, it
alters the activity of another molecule. This process is
repeated until the last molecule is activated and the cell
function involved is carried out. Abnormal activation
of signaling pathways can lead to cancer, and drugs are
being developed to block these pathways. These drugs
may help prevent cancer cell growth and kill cancer cells.
Standard of care The intervention or interventions
generally provided for a certain type of patient, illness,
or clinical circumstance. The intervention is typically
supported by evidence and/or expert consensus as
providing the best outcomes for the given circumstance.
Soft tissue sarcoma A group of cancers that arise in
soft tissues of the body such as the muscles, tendons, fat,
blood vessels, lymph vessels, nerves, and tissues around
joints. Both children and adults can develop soft tissue
sarcomas. Rhabdomyosarcoma is the most common type
of soft tissue sarcoma in children, while gastrointestinal
stromal tumors are the most common in adults.
T cell A type of immune cell that protects the body from
invading microorganisms and other foreign substances
and that destroys infected and malignant cells. A T cell
is a type of white blood cell. Also called T lymphocyte.
Thyroid cancer Cancer that arises in the thyroid gland (a
gland at the base of the neck that makes hormones that help
control heart rate, blood pressure, body temperature, and
weight). The four main types of thyroid cancer — papillary,
follicular, medullary, and anaplastic — are named for the
kind of cells found in the cancer and how the cancer cells
look under a microscope.
Tumor An abnormal mass of tissue that results when cells
divide more than they should or do not die when they
should. Tumors may be benign (not cancer) or malignant
(cancer). Also called neoplasm.
Tumor microenvironment The cells, molecules, and blood
vessels that surround and feed a cancer cell. A cancer can
change its microenvironment, and the microenvironment
can affect how a tumor grows and spreads.
Urothelial carcinoma The most common type of bladder
cancer. It begins in urothelial cells that line the inside
of the bladder. These cells are able to change shape and
stretch when the bladder is full.
Vaccine A substance or group of substances meant to
cause the immune system to respond to a tumor or to
microorganisms such as bacteria or viruses. A vaccine
can help the body recognize and destroy cancer cells or