Cancer Glossary

Cancer Glossary

Your DNA Tells a Specific Story

Each story will help you understand what a particular gene does and why it’s relevant in cancer. We don’t provide answers about your care options, but we do help you become conversant in your disease so you can better partner with your doctor. Share this information with your family and caregivers to build common understanding.

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A

Acquired mutation—a mutation in one or a small handful of cells that is acquired over the course of a person’s lifetime, due to environmental exposure or aging. Acquired mutations are also known as somatic mutations. Acquired mutations in certain genes can accumulate over time, leading to cancer.

 

Adjuvant therapy—Additional therapy given after primary treatment for cancer, to help lower the risk of recurrence.

 

Allogenic transplant—tissue transplant that comes from another person, not from you.

 

Autologous transplant—tissue transplant using your own cells.

 

B

Base pair—DNA has a structure like a twisted ladder. The rungs on the ladder are made up of pairs of molecules, known as “base pairs.” During genetic sequencing, computers “read” one side of the ladder, and spit out a string of letters representing the order of pairs according to the following method: cytosine always pairs with guanine (C pairs with G), and adenine with thymine (A pairs with T).

 

Bioinformatics—A field of science and medicine that uses computer programming, statistics, math, and engineering to interpret data. Essentially, it is the sorting of vast quantities of data to help improve health outcomes and discover new drug targets.

 

Biomarker—a molecule, such as a bit of DNA, a protein, or a hormone, that gives doctors insight into how a patient’s illness will behave.

 

Biopsy­­—the practice of using surgery or needles to take a sample of tumor tissue. Used to diagnosis cancer or to examine its biology.

 

Biospecimen—a sample of material from a patient’s body, for example, urine, blood, or tumor sample.

 

C

Case control study—a study that looks at a group of people who have a particular disease and a control group of people who do not. Researchers then try to figure out which risk factors people in each group have been exposed to. The aim is to learn about risk factors for diseases like cancer.

 

Chemotherapy—drugs used to treat cancer. Comes from “chemo-,” meaning “chemical” + “therapy.” Sometimes referred to as “chemo.”

 

Clinical epidemiology—studies how to evaluate and apply the results of clinical research.

 

Cohort—a group that shares one or more characteristics, for example, lung cancer patients taking a certain drug, people born in 1964, or people who use talcum powder. Researchers often sort patients into groups called “cohorts” during studies.

 

Cohort study—a study that looks at different groups of people and compares their outcomes over time.

 

Completion date—the anticipated date when research is complete. Many clinical trials have a Study Completion Date (an estimate of when the study will be complete) as well as a Primary Completion Date (an estimate of when most of the data will be collected).

 

Comorbidity or comorbidities—when a patient has more than one health-related condition at once, they are said to have a comorbidity. For example, a patient with asthma and lung cancer has a comorbidity.
Concomitant—existing alongside.

 

Control—in clinical trials, researchers oven divide their patients into two groups: an experimental group that receives the treatment being tested, and a control group that receives the best standard treatment. Using a control group helps the researchers draw conclusions about whether the treatment really works.

 

Core biopsy—uses a hollow needle to take a small sample of a tumor.

 

CT scan— A painless scan used to get pictures of the inside of the body and typically provides greater detail than a traditional X-ray. During a CT scan, the patient lies on a table which passes through a large x-ray machine. Sometimes patients also receive contrast die during a scan to make certain parts of the body more visible in the image. CT stands for “computerized tomography”—during the scan the machine takes pictures from a variety of angles that are composited together to provide 3-D images of the body’s various tissues.

 

Cytologically/Cytologic—cytology is the study of cells. Looking at something cytologically or performing a cytologic analysis means looking at it on the cellular level.

 

E

Efficacy study—a clinical trial that examines whether a treatment produces the desired effect under ideal conditions. Often contrasted with an effectiveness study.

 

Effectiveness study—a clinical trial that examines whether a treatment produces the desired effect in real-world usage. It’s sort of like a road test for a treatment, compared with an efficacy study, which looks at the treatment in controlled, perfect conditions.

 

Endoscopy—a nonsurgical procedure in which a physician takes pictures of a patient’s innards using a camera and light mounted on a small flexible tube. Most often, the word “endoscopy” refers to a scan of the digestive tract, but other parts of the body can be examined with this method.

 

Epidemiology—a discipline that studies how frequent and how prevalent diseases are in large groups of people.

 

F

FISH Analysis—a test that can detect alterations in genes associated with some types of cancer. Works by attaching colored dyes to certain parts of particular chromosomes to make alterations visible to a fluorescent microscope. Sometimes used to diagnose some types of leukemias, lymphomas, sarcomas, bladder cancer, and to detect whether breast cancer has an abundance of HER receptors.

 

Fusions—a type of genetic alteration in which two separate genes become fused together.

 

G

Gene therapy—introduces genes into the body to treat diseases. In cancer patients, this can mean introducing material into the tumor to correct wonky genes that are driving tumor growth.

 

Genomics—the study of a person’s DNA as a complete set.

 

Genotype—a person’s unique genetic makeup. It can also refer to one gene or a set of genes of a particular person. Typically distinguished from phenotype, which describes a person’s physical characteristics—phenotype is the physical manifestation of a person’s genetic code.

 

Germline mutation—a mutation that is inherited from generation to generation. Germline mutations are not just present in a handful of cancer cells; they are present in nearly every cell of the body. Germline mutations are also known as inherited mutations. When combined with acquired or somatic mutations over time, they lead to a high rate of cancer in some families.

 

H

High-throughput sequencing—a catchall term used to describe several modern sequencing methods that sequence DNA and RNA more quickly and cheaply than previous methods. Sometimes called next generation or next-gen sequencing.

 

Histology—histology is the study of the structure, composition, and function of tissues, and it is one of the major ways cancer is classified. In a patient, cancer is typically named by its site of origin, but it is also defined histologically, by the sort of tissue it starts in. Histologically speaking, cancer is grouped into major categories including carcinoma, leukemia, lymphoma, myeloma, sarcoma, and others.

 

Histopathology—part of the discipline of pathology that focuses on looking at tissue samples rather than single cells or cell fragments (cytology). In histopathology, tissue samples are preserved and put onto slides so that a trained professional, the histopathologist, can examine them for signs of cancer.

 

I

Immunotherapy—a therapy that treats or prevents disease by gearing up the body’s immune response.

 

Informed Consent—before enrolling in a clinical trial, by law, researchers must obtain consent from patients. Not just any kind of consent, but informed consent. This means researchers must provide patients with information about the study, including its risks, benefits, and the methods used. Researchers must provide this information in language the patient can understand, and give patients time to ask questions and consult with friends, medical professionals, and family. After weighing this information, if the patient still voluntarily enrolls in the study, they are said to have given “informed consent.” The informed consent process does not stop when a patient enrolls in a study—researchers must keep them up to date about risks, benefits, and procedures as more information is uncovered.

 

Inherited cancer syndrome—also known as family cancer syndrome. Certain cancer runs in some families. This could be because everyone shares a habit, like chain smoking, but in rare cases—about 5 to 10 percent of all cases of cancer—it is due to an inherited genetic mutation, passed down from generation to generation. All cancer boils down to genetic errors that accumulate over time, until cells go haywire and start replicating to excess. People with an inherited cancer syndrome have a higher likelihood of developing cancer because they begin life with a mutated gene in virtually every cell of their bodies. If you envision the march from normal cell growth to cancer as a race, essentially, people with inherited cancer syndromes have a head start.

 

Inherited mutations–a mutation that is inherited from generation to generation. Inherited mutations are not just present in a handful of cancer cells; they are present in nearly every cell of the body. Inherited mutations are also known as germline mutations. When combined with acquired or somatic mutations over time, they lead to a high rate of cancer in some families.

 

Inhibitor—a drug that slows or stops the action of a particular cellular process.

 

Interventional study—a clinical trial in which patients receive new treatments, or the best standard care, if they are part of the control group.

 

Investigational new drug–a treatment used in a clinical trial that has not yet been approved by the FDA. Researchers will be trying to find out more about it, including the safest dosage, its side effects, and whether it is effective for treating different types of cancer.

 

 

M

Magnetic resonance imaging (MRI)—a noninvasive test that uses magnetic waves to detect the location of tumors.

 

Magnetic resonance spectroscopy (MRS)—a noninvasive test that uses magnetic waves to examine the chemical composition of tissues in the body. Typically used together with an MRI.

 

Masking—also known as blinding. In a clinical trial that uses masking, the researchers or the participants or both may not know who is receiving which treatment.

 

Metastasis—cancer is named for the organ it begins in. When it spreads to new locations and sets up shop, the result is a metastasis. The cancer still retains the name of its tissue of origin. If breast cancer metastasizes to the liver, it is still breast cancer. Metastasis is correlated with a worse prognosis than cancer that is confined to its area of origin.

 

Monoclonal antibodies—lab-produced molecules that bind to substances in the body, including cancer cells. Monoclonal antibodies mimic the behavior of the immune system and are engineered to specifically target a given substance in the body. Non-proprietary drug names that end in –mab are monoclonal antibodies. Monoclonal antibodies are immunotherapy.

 

Mutation—an alteration in the body’s genetic code that is permanent. Mutations may be caused by environmental exposure or by errors made during the cell replication process (somatic mutations). Sometimes, they are inherited from one’s parents (germline mutations). These errors accumulate over time. When enough vital parts of DNA are screwed up in one or a few cells, cancer can result. There are several categories of mutations.

 

Types of Mutations—there are several different ways a gene can be mutated. In a substitution mutation, one letter from the genetic code is switched out for another. In an insertion mutation, one to a thousand base pairs might be inserted into a gene. In a deletion mutation, some base pairs are deleted. In frameshift mutation, the way the DNA is read gets off. DNA is divided into “words” called codons that are three base pairs long; each codon encodes an amino acid. In a frame shift mutation, “The cat ate her rat” would become “hec ata the err at.” In a fusion mutation, the parts of two genes are fused together.

 

N

Neoadjuvant therapy—therapy aimed at shrinking the tumor before the main treatment, typically surgery.

 

Neoplasm—a synonym for “tumor.”

 

Next-generation sequencing (NGS)—a catchall term used to describe several modern methods that sequence DNA and RNA more quickly and cheaply than previous methods. Also known as high-throughput sequencing

 

 

O

Observational study—a study in which no treatment is given. Instead, the researchers measure the outcomes for different patients progressing down their treatment paths, and try to draw conclusions about what worked and what didn’t.

 

Open label study—a study in which the researchers and the patient are aware of the treatment being given. (See also: masking.)

 

P

Pathology report—a description of cells and tissues based on their examination by a pathologist, a scientist specially trained to identify diseases by looking at samples under a microscope. A pathology report is sometimes used to diagnose cancer.

 

PCR analysis—a method labs use to make many copies, even millions of copies of a piece of DNA. This method helps process DNA for sequencing. PCR stands for polymerase chain reaction.

 

Phenotype—the physical manifestation of a person’s genetic code. Typically distinguished from genotype, which is a person’s unique genetic makeup and can refer to one gene or a set of genes of a particular person. The gene for brown hair is the genotype, the brown hair on a person’s head would be the corresponding phenotype.

 

Pilot study—Before researchers run a major trial, they may run a pilot study. The point of the pilot study is to help researchers figure out whether their methods will work, for example, whether patients are willing to be put into random groups, whether people are likely to complete questionnaires, and how medical professionals will recruit for the study. Sometimes, the results from the pilot study are also used in the main study results.

 

Principal Investigator—the main person or people who are in charge of a clinical trial. The principal investigator makes the plan for the study, called a protocol, analyzes data, and reports results.

 

Prognostic value—predictive value. Researchers are constantly searching for factors, such as biomarkers that can help them estimate a patient’s chance of recurrence, recovery, or metastasis.

 

Protein expression—when a cell produces a protein, that protein is said to be “expressed.” Proteins are the end result of a long cellular process that begins with DNA.

 

Proteomics—the study of proteins, including their structures, functions, and how they interact within the cell.

 

Protocol—the detailed plan for a clinical trial that explains why the study is being done, how it will be done, who will be involved, and what kind of treatments or tests it will involve.

 

R

Radiation therapy—uses high energy radiation to shrink tumors. The radiation can come from outside the body (external-beam radiation), from radioactive substances placed in the body near cancer cells (internal radiation therapy, or brachytherapy), or from a radioactive substance that travels through the blood to kill cancer cells (systemic radiation). Around half of cancer patients receive radiation therapy during their treatment.

 

Randomized trial—in a randomized trial, several treatments may be compared. The patients are assigned randomly into groups receiving the different treatments—neither they nor the researchers may choose one treatment or the other.

 

Resection—removal of all or part of an organ through surgery.

 

S

Somatic mutation—a mutation in one or a small handful of cells that is acquired over the course of a person’s lifetime, due to environmental exposure or aging. Somatic mutations are also known as acquired mutations. Somatic mutations in certain genes can accumulate over time, leading to cancer.

 

Stage—when cancer is diagnosed, it is given a stage, ranging from I to IV in increasing severity. Cancer that is stage I is confined to its organ of origin, while stage IV cancer has spread to other tissues.

 

Standard of care—a treatment that medical experts agree is the best treatment for a particular stage and type of cancer and that is widely used.

 

 

T

Tolerability—the extent to which patients can tolerate unpleasant side effects of a treatment.

 

Trial sponsor—the government agency, company, person, or health care institution that pays for, initiates, and manages a clinical trial.

 

Types of Mutations—there are several different ways a gene can be mutated. In a substitution mutation, one letter from the genetic code is switched out for another. In an insertion mutation, one to a thousand base pairs might be inserted into a gene. In a deletion mutation, some base pairs are deleted. In frameshift mutation, the way the DNA is read is off. DNA is divided into “words” called codons that are three base pairs long; each codon encodes an amino acid. In a frame shift mutation, “The cat ate her rat” would become “hec ata the err at.” In a fusion mutation, the parts of two genes are fused together.