126 AACR CANCER PROGRESS REPORT 2016
among adults in the United States. CLL arises in
lymphocytes, most commonly B lymphocytes, in the
bone marrow, which then enter the blood. It is usually
slow growing, but in some people, it can be fast growing.
Clinical trial A type of research study that tests how well
new medical approaches work in people. These studies
test ne w methods for screening, preventing, diagnosing,
or treating a disease. Also called clinical study.
Colonoscopy Examination of the inside of the colon
using a colonoscope that is inserted into the rectum. A
colonoscope is a thin, tube-like instrument with a light and
a lens for viewing. It may also have a tool to remove tissue
to be checked under a microscope for signs of disease.
Colorectal cancer A group of cancers that start in the
colon or the rectum. More than 95 percent of colorectal
cancers are adenocarcinomas that arise in cells forming
glands that make mucus to lubricate the inside of the colon
and rectum. Before a colorectal cancer develops, a growth
of tissue or tumor usually begins as a noncancerous polyp
on the inner lining of the colon or rectum. Most polyps
can be found—for example, through colonoscopy—and
removed before they turn into cancer.
Computational biology The development of data-analytical and theoretical methods, mathematical
modeling, and computational simulation techniques
and their application to the study of biological, behavioral,
and social systems.
Computed tomography (C T) A series of detailed pictures
of areas inside the body taken from different angles. The
pictures are created by a computer linked to an X-ray
machine. Also called CAT scan, computerized axial
tomography scan, and computerized tomography.
Death rate/mortality rate The number of deaths in a
certain group of people in a certain period of time. Death
rates may be reported for people who have a certain
disease; who live in one area of the country; or who are
of a certain gender, age, or ethnic group.
Deoxyribonucleic acid (DNA) The molecules inside
cells that carry genetic information and pass it from one
generation to the next.
Drug resistance The failure of cancer cells, viruses, or
bacteria to respond to a drug used to kill or weaken them.
The cells, viruses, or bacteria may be resistant to the drug
at the beginning of treatment or may become resistant
after being exposed to the drug.
Epidermal growth factor receptor (EGFR) A protein
found on the surface of some cells to which epidermal
growth factor binds, causing the cells to proliferate. It is
found at abnormally high levels on the surface of many
types of cancer cells, including many types of lung cancer
cells, so these cells may divide excessively in the presence
of epidermal growth factor. Also called ErbB1 and HER1.
Electronic cigarette (e-cigarette) A battery-powered
device that delivers nicotine by vaporizing a nicotine
solution, rather than by combusting tobacco as do
traditional cigarettes and cigars.
Endpoint In clinical trials, an event or outcome that
can be measured objectively to determine whether the
intervention being studied is beneficial. The endpoints of
a clinical trial are usually included in the study objectives.
Some examples of endpoints are survival, improvements
in quality of life, symptom relief, and disappearance of
Epigenetics The study of heritable changes in gene
expression or cellular phenotype caused by mechanisms
other than changes in DNA sequence. Examples of
such changes might be DNA methylation or histone
deacetylation, both of which serve to suppress gene
expression without altering the sequence of the silenced
Epigenetic mark A chemical mark on DNA (see
Deoxyribonucleic acid) and histones (see Histone) that
can control the accessibility of genes. The collection of
epigenetic marks across the entire genome is referred to
as the epigenome.
Familial adenomatous polyposis (FAP) An inherited
condition in which numerous polyps (see Polyp) can
develop in the colon and rectum. It increases the risk of
colorectal cancer. Also called familial polyposis.
Five-year survival rate The percentage of people in a
specific group, for example, people diagnosed with a
certain type of cancer or those who started a certain
treatment, who are alive 5 years after they were diagnosed
with or started treatment for a disease, such as cancer. The
disease may or may not have come back.
Follicular lymphoma A form of non-Hodgkin lymphoma
that is usually slow growing. It begins in immune cells
called B cells, which grow as groups to form nodules. It
initially affects the lymph nodes and may spread to the
bone marrow or spleen.