Absorb/absorption: to take in; taking up of liquids by solids; passage of a substance through some surface of the body into body fluids and tissues

ACTH: adrenocorticotropic hormone (or corticotrophin); a polypeptide hormone secreted by the pituitary gland; part of the hypothalamic-pituitary-adrenal axis

Adipogenesis: the formation of fat or fatty tissue

Adipose tissue: a connective tissue consisting chiefly of fat cells that come from dietary fats or produced by the body; functions as an endocrine organ, producing hormones such as leptin, etc.

Adiposity: obesity

Adrenarche: underarm/pubic hair growth during puberty induced by a normal increase in activity of the adrenal cortex which releases adrenal androgens

Advocate: one who promotes an issue or supports a particular cause; to plead on behalf of someone or something

Aliquot: a measured portion of a sample collected for analysis; the sample could be biologic (blood, urine, etc.) or environmental

Alkylphenols: chemicals used in the production of detergents, plastics and some pesticides; tend to persist in the environment and can have estrogen-like properties

Analyte: the substance measured by a laboratory test

Aneuploidy: the state of having an abnormal number of chromosomes

Angiogenesis: the formation of new blood vessels; important in tumor growth

Anthropometry: measurements of the human body: height, weight, skin fold thickness, etc.

Antibodies: special proteins that are made by the immune system to attack and neutralize foreign substances called antigens

Anti-estrogen: a substance that blocks the activity of estrogen

Antigens: foreign substances (viruses, bacteria or abnormal cell changes) that are attacked by the immune system

Antineoplastic: preventing the development, maturation or spread of cancer (neoplastic) cells

Apoptosis: programmed cell death; a process that limits cell growth

Aromatase: an enzyme or group of enzymes that converts androgens (testosterone) into estrogens

Asbestos: a strong, noncombustible mineral fiber used in the past for fireproofing and insulation; it can pollute air and water and cause cancer or asbestosis when inhaled.

Atrazine: a widely used agricultural herbicide; mainly used on corn and soybean crops


B cells (also called B lymphocytes): white blood cells that produce antibodies and protect against infection and disease

Bacteria: any of a large group of single-cell, microscopic organisms that live in soil, water, plants, organic matter, animals and/or people; some can cause disease.

BCA (Breast Cancer Alliance of Greater Cincinnati): a breast cancer advocacy and educational organization founded in 1994

BCERC (Breast Cancer and the Environment Research Centers): funded by the National Institute of Environmental Health Sciences and the National Cancer Institute; centers are based at the University of California-San Francisco, University of Cincinnati, Michigan State University and Fox Chase Cancer Center.

Benign proliferative breast disease: a group of noncancerous conditions that may increase the risk of developing breast cancer; examples include ductal hyperplasia, lobular hyperplasia and papillomas.

Benign tumor: a noncancerous growth that does not invade nearby tissue or spread to other parts of the body

Benzene: a carcinogenic compound widely used in the chemical industry; also found in tobacco smoke, vehicle emissions and gasoline fumes

Benzo(a)pyrene: a polycyclic aromatic hydrocarbon found in coal tar, automobile exhaust (especially diesel engines), wood smoke and charbroiled foods; causes changes in the chromosomes of a gene(s) (mutagenic) and is highly carcinogenic

BFR (brominated flame retardants): over 70 variants are produced to treat electronics, furniture and clothing; some are considered persistent organic pollutants which are known to accumulate in the body.

Bile: a secretion of the liver; bile is stored in the gallbladder, discharged into the duodenum (small intestine) during eating, aiding the digestion of lipids.

Bioaccumulation: the increase in concentration of a substance(s) in an organism or a part, e.g., fat tissues, of the organism; the organism has a higher concentration of the substance than the concentration in the organism’s surrounding environment.

Bioconcentration: bioaccumulation of substances taken in by the organism from water only; the rate of uptake from water is greater than the rate of excretion.

Bioinformatics: the science of managing and analyzing biological data using advanced computing techniques; especially important in analyzing genome research data

Biological monitoring: the periodic measurement of toxic substances or their metabolites in samples of blood, tissues, secretions, excretions (urine, stool, breast milk, seminal fluid) or exhaled air

Biologically effective dose: the amount of a deposited or absorbed chemical that reaches the cells or target site where an adverse effect occurs or where the chemical interacts with a membrane surface

Biomagnification (or bioamplification): the increase in concentration of a substance in a food chain (not an organism); persistent organic pollutants are compounds that biomagnify. (See POP.)

Biomarker: a substance detected in the blood, urine, other body fluids and/or tissues used to measure or indicate exposure to or alterations caused by a chemical compound; also used to detect the presence/progress of a disease (tumor marker)

Biomarker of effect: a substance detected in body fluids and/or tissues used to measure or indicate a biological response to an environmental chemical which gives a measure of toxic effect; biological responses may be at the molecular, cellular or whole organism level.

Biomarker of exposure: a substance detected in body fluids and/or tissues used to measure or indicate exposure to a chemical compound

Bioremediation: any process that uses microorganisms, fungi, green plants or their enzymes to clean a contaminated environment to its original condition

BMI (body mass index): used to gauge whether or not a person is overweight; it is calculated by dividing a person’s weight (kilograms) by her/his height (meters2).

BPA (Bisphenol A): used in the production of epoxy resins that line food cans, bottle tops and water supply pipes; also used in production of polycarbonate plastics found in many food and drink packaging; known to have estrogenic effects

BRCA1 and BRCA2: two of the primary genes involved in breast cancer; classified as tumor suppressor genes


Caloric restriction: regulation of the consumption of calories

Cancer: a term for diseases in which abnormal cells divide without control; cancer cells can invade nearby tissues and can spread through the bloodstream and lymphatic system to other parts of the body (metastasize).

Carcinogen: a substance that causes cancer

Carcinogenesis: a process by which normal/healthy cells turn into cancer cells

Carcinoma: a cancerous growth made up of epithelial cells: cells from tissues that form the covering around organs, such as lung, liver, or breast, or the lining of blood vessels

Carcinoma in situ: a cancer that involves only the cells in which it began and has not spread to nearby tissues

Case control: a type of epidemiology study design in which persons with and without a disease (or exposure of interest) are studied to identify factors associated with the disease

CDC (Centers for Disease Control and Prevention): a major component of the US Dept. of Health and Human Services; provides facilities and services for the investigation, identification, prevention and control of disease

Cell: the basic unit of all living things; each cell contains essential components enclosed by a membrane.

Cell differentiation: a process by which immature/unspecialized cells become mature/specialized, i.e., have a specific function.

Cell proliferation: an increase in the number of cells as a result of cell division

Chemoprevention: the use of dietary substances and/or drugs to delay the development of cancer or stop it from coming back

Chemotherapy: treatment of infections and other diseases with chemical agents/drugs

Chromatin: mass of genetic material (DNA and proteins) compacted in the cell nucleus; it forms chromosomes.

Chromosome: a long strand of DNA that contains about 1,000 genes which carry hereditary information; there are 46 chromosomes in each cell of the body, except reproductive cells (egg and sperm) that contain only 23 chromosomes.

Clinical trial: a type of research study that uses volunteers to test new methods of screening, prevention, diagnosis or treatment of a disease; also called a clinical study

Cohort: a collection or sampling of individuals who share a common characteristic (e.g., the same age group) or experience (e.g., employment in a particular industry during or for a specified period)

Complementary and alternative medicine: forms of treatment that are used in addition to (complementary) or instead of (alternative) standard medical treatments; examples include dietary supplements, mega-dose vitamins, herbal preparations, special teas, acupuncture, massage therapy, spiritual healing, meditation, etc.

Confidence interval (CI): a measure of the reliability of a statistical parameter (for example a population mean); reported as ± some number or as a numerical range. The CI is reported for a specified confidence level, most commonly 90%, 95% or 99%.

Confidence level: reflects the certainty that the statistic being presented is accurate; reported as a percentage, e.g., 90%, 95% or 99%.

Confounding: a variable that is associated with the independent and dependent variables in a statistical analysis; confounders must be controlled for in statistical analyses to avoid making a false conclusion about a probable causal relation between the two variables

Congeners: two or more things that are similar or closely related in structure, function or origin; chemical compounds similar in composition and effect

COTC (Community Outreach and Translation Core): a component of the Breast Cancer and the Environment Research Centers; responsible for integrating breast cancer advocates into the BCERCs and communicating research findings to the nonscientific public and policy analysts

Corticosteroids/corticosterone: a hormone of the adrenal cortex; it influences carbohydrate, potassium and sodium metabolism; it is essential for normal absorption of glucose, the formation of glycogen in the liver and tissues, and the normal utilization of carbohydrates by the tissues.

Cotinine: a major metabolite of nicotine found in blood and urine; currently regarded as the best biomarker for exposure of nonsmokers to environmental tobacco smoke

Critical period: a time in the early stages of an organism’s life during which it displays a heightened sensitivity to certain environmental stimuli; the organism develops in particular ways due to experiences at this time

Cross-sectional: a type of epidemiology study design in which a randomly selected sample of persons from a community, industry or population are studied to assess the factors associated with the incidence or prevalence of a disease/condition

Cultural diet: a diet given to offspring in utero and throughout their lifespan

Cutaneous breast cancer: cancer that has spread from the breast to the skin

Cytotoxic therapy: drug treatment that is designed to inhibit the proliferation of cells or to selectively destroy abnormal cells


DCIS (ductal carcinoma in situ or intraductal carcinoma): a noninvasive, precancerous condition in which abnormal cells are found in the lining of a breast duct; the abnormal cells have not spread outside the duct to other tissues in the breast. DCIS may become invasive cancer and spread to other tissues; at this time, it is not known how to predict which lesions will become invasive.

DDT (dichloro-diphenyl-trichloroethane): the first modern pesticide; banned in the U.S. in the early 1970s because of its persistence and toxicity in the environment

Dermal: relating to the skin (epidermis).

DES (diethylstilbestrol): an artificial estrogen used in the past to prevent miscarriage; daughters of women who took DES have a higher risk of vaginal cancers.

DHHS (US Department of Health & Human Services): a cabinet-level department of the U.S. government responsible for the functions of various federal social welfare programs, health delivery agencies and research institutes

Differentiation: the acquisition of functions and forms different from those of the original; in cancer, differentiated tumor cells resemble normal cells and tend to grow slower than undifferentiated or poorly differentiated tumor cells which lack the structure and function of normal cells and grow faster.

Dioxin: a contaminant of the herbicide 2,4,5-T; widely used throughout the world as a defoliant and for weed control; highly toxic to humans and stable in the environment

DMBA (dimethyl benz(a)anthracene): an experimental carcinogen, not found in nature, synthesized in the lab to be used as a test carcinogen. DMBA serves as a model carcinogen for the class of PAHs (polycyclic aromatic hydrocarbons), which include many carcinogens; DMBA-generated breast cancer in the lab closely mimics human tissue changes.

DNA (deoxyribonucleic acid): the molecule inside the cell that carries genetic information and is passed on from one generation to the next

DNA adduct: the binding of an environmental chemical with DNA, causing DNA damage; sometimes used as biomarkers of effect in research

Dose dependent: the effect of a chemotherapeutic agent or environmental toxin is proportionate to the treatment or exposure dose, respectively

Dose limiting (side effects): drug reaction(s) that prevent administering the drug at a higher dosage

Dose rate: the rate at which a drug or toxin is administered over a given period of time

Double blinded: a type of clinical study in which neither the medical/research staff nor the study participants know whether individual participants are receiving the study treatment or placebo

Ductal extension: measured as the distance from the midpoint of the lymph node to the leading edge of the ductal tree

Ductal tree: refers to the branch-like formation of the mammary gland ducts


Eligibility (or inclusion) criteria: requirements that must be met for an individual to be included in a research study; examples include age or type and stage of cancer

Endocrine disruptors: a diverse group of environmental chemicals that are capable of interfering with hormones produced in the body; also called xenoestrogens

Endocrine system: a network of ductless glands and other structures in the body that secrete hormones directly into the blood, affecting the function of specific organs and processes like metabolism and growth

Endocrine therapy: treatment that adds, blocks or removes hormones in order to slow or stop the growth of certain cancers (such as breast or prostate); also called hormone therapy, hormonal therapy or hormone treatment

Endocrinology: the study of the anatomic, physiologic and pathologic characteristics of the endocrine system and the treatment of endocrine problems

Endogenous: originating or produced within the organism or one of its parts (The opposite is exogenous.)

Endometrium: the layer of tissue that lines the uterus

Endothelial: a type of cell found in the lining of blood vessels, lymph nodes and the heart

Enterohepatic circulation: refers to the circulation of bile from the liver (where it is produced) to the small intestine (where it aids in the digestion of fats and other substances) and then back to the liver

Environment: any and all conditions external to an organism that can affect its life, development and/or survival

Enzyme: a substance that speeds up chemical reactions in organic matter, including the body; enzymes act on substrates to catalyze chemical reactions.

EPA (Environmental Protection Agency): develops and enforces national standards and regulations that implement environmental laws enacted by Congress.

Epidemiology: the study of the patterns of diseases in human populations and the factors that influence the incidence, severity, morbidity and mortality of diseases

Epigenetic: modifications to the structure of the DNA, but not the DNA sequence, that result in changes in gene function (the organism’s phenotype)

Epithelial cells: cells arranged in one or more layers that form part of a covering or lining of a body surface; these cells usually adhere to each other along their edges and surfaces.

Epithelium: membranous tissue composed of one or more layers of cells (epithelial cells), forming the covering of most internal and external surfaces of the body as well as the lining of vessels, body cavities, glands and organs

Estradiol: the most potent naturally occurring human form of the hormone estrogen

Estrogen receptor (ER): protein normally found in mammary cells to which estrogens attach and thereby exert their biological function

  • ER negative cancer: breast cancer cells that do not have the estrogen receptor; these ER-negative tumors do not need estrogen to grow and usually do not respond to hormone (anti-estrogen) therapy.
  • ER positive cancer: breast cancer cells that have the estrogen receptor; these ER-positive tumors need estrogen to grow and usually do respond to hormone (anti-estrogen) therapy that blocks ER function and subsequent tumor growth.

Estrogens: the family of hormones that promote the development of female secondary sex characteristics

Estrus cycle: the recurring physiologic changes that are induced by reproductive hormones in most mammalian placental females; estrus (or heat) is signaled to the males of the species when ovulation is imminent. (Humans undergo a menstrual cycle in which the ovulation process is concealed.)

Etiology: origin or cause(s) as in the cause(s) of a disease or abnormal condition; factors which produce or predispose toward a certain disease or disorder

ETS (environmental tobacco smoke): ambient smoke produced by persons smoking cigarettes; also known as secondhand smoke

Exclusion criteria: eligibility criteria used to exclude individuals from participating in a study, often because a preexisting condition puts the individual at-risk in the study protocol or the condition potentially interferes with the study outcome

Excretion: the process of eliminating waste products of metabolism and other non-useful materials from an organism

Exogenous: originating from or produced outside of the organism

Experimental design: a type of research study design that alters a risk factor

Exposure: contact of the outer or inner parts of an organism to a biologic, chemical or physical agent

Exposure assessment: prescribed documentation of an environmental agent’s contact with and entry into an organism (especially the human body); focuses on sources and concentrations of the agent(s) in the environment, exposure pathways and probable internal dose

Exposure pathway: probable routes by which an organism comes in contact with a biologic, chemical or physical agent; refers to the behaviors of the organism that expose it to the agent as well as the agent’s characteristics that enable it to come into contact with the organism

Extracellular: outside the cell(s)


Familial cancers: cancers that occur in families in which a mutated gene, associated with an elevated risk of developing a particular cancer(s), is passed on from one generation to the next. (BRCA1 and BRCA2 genes are examples: If a woman inherits one of these genes, she has a higher risk of developing breast and/or ovarian cancer.)

Family history: a record of an individual’s current and past illnesses and those of her/his grandparents, parents, aunts/uncles, siblings, children and other family members; can be used by geneticists and genetic counselors to assess risk for certain diseases

Fatty acids: building blocks of fat, essential for cell energy and growth

  • Saturated fatty acids: found in animal fats and tropical oils (palm and coconut); can raise the levels of LDL (bad) cholesterol
  • Polyunsaturated fatty acids: found mainly in fish, corn, soybean and safflower oil; may help reduce cholesterol levels (See also Omega-3 fatty acids.)

Fetal programming: an early stimulus or insult operating at a critical or sensitive period of prenatal development that results in a long-term change in the structure or function of the organism

Fibrocystic breast disease: noncancerous breast tissue build-up; although, some types of fibrocystic breast tissue changes can lead to an increased risk for breast cancer

Fine needle aspiration: the removal of fluid or tissue with a needle for examination under a microscope; also called needle biopsy

FISH (fluorescent in situ hybridization): a laboratory technique used to determine the presence/amount of a certain gene in a cell

Focus group: a qualitative research technique in which an experienced moderator leads about eight to 10 participants through a semi-structured discussion on a select topic


Gavage: administration of a liquid or semiliquid through a tube, inserted in the nose and passed down the throat and into the stomach

Gene knockout: a laboratory term used to describe a type of mouse or cells whose DNA sequence has been intentionally deleted or inactivated for research purposes

Genes: pieces of DNA, or heredity units, which are passed from parents to their children; genes contain the information for making specialized proteins that are responsible for specific traits, such as eye color, height, etc.

Genetic counseling: a general process in which a trained genetic counselor documents generations of an individual’s family history (pedigree) to assess their or their offspring’s risk of a select disease(s)/disorder(s); based on the family history, the pros/cons of genetic testing may be discussed and/or the results interpreted

Genetic markers: alterations in DNA that may indicate an increased risk of developing a specific disease or disorder

Genetic susceptibility: an inherited increased risk of developing a certain disease or disorder

Genetic testing: analysis of DNA to look for genetic alteration(s) that may indicate an increased risk for developing a disease(s) or disorder

Genome: the complete genetic material of an organism

Genomics: the comprehensive study of whole sets of genes and their interactions

Genotype: the genetic makeup/constitution of an organism; distinguished from its physical appearance (phenotype)

Germline mutation: a gene mutation, present in the egg or sperm, that can be passed from parent to a child

Glucocorticoids: a general classification of adrenal cortical hormones; primarily active in protecting against stress and in affecting protein and carbohydrate metabolism

Glucose: sugar, a source of energy; formed during digestion and the metabolism of carbohydrates in the body

Gonadotropins: hormones secreted by the pituitary gland; capable of promoting gonadal (ovaries and testes) growth and function


H and E: a specific immunohistochemical stain in which hematoxylin and eosin are used to stain normal and pathologic structures in a cross-section of the mammary gland

Habitus: the physical characteristics of a person

Herbicide: a chemical that destroys plants and weeds

Histology: the science concerned with fine cell structures, tissues and organs in relation to their function

Homeostasis: the property of a living organism to regulate its internal environment so as to maintain a stable, constant condition, i.e., equilibrium

Hormonal profile: analysis of a substance (generally serum) to determine the levels of progesterone, testosterone, ß-estradiol, cortisol, DHEA-S and melatonin

Hormone: a chemical substance produced and secreted by an endocrine (ductless) gland; transmitted by the blood to another tissue on which it has a specific effect

Hydrolysis: any chemical reaction in which water is one of the reactants; the combination of water with salt to produce an acid and a base; the reverse of neutralization

Hyperplasia: when cells in an organ are growing faster than normal

Hyperplastic: relating to hyperplasia; the state of having an increase in number of normal cells in a tissue or organ

Hypothalamic-pituitary-adrenal axis: a complex, multidirectional pathway between the hypothalamus of the brain, the pituitary gland and the adrenal gland; controls reactions to stress and regulates various body processes including digestion, the immune system, mood, sexuality and energy usage

Hypothesis: a best estimation, based on scientific knowledge and assumptions, of the results of an experiment; it usually describes the anticipated relationship among variables in an experiment. A scientific hypothesis must be 1) testable and 2) falsifiable.


Immunohistochemistry: analytical methods based on dyes and antibodies, used to locate and identify markers in cancer tissues

Imprinting: events during gestation and/or early postnatal stages that may have long term consequences for health

Incidence rate: the number of people who develop a disease divided by the number of people at risk of developing the disease in a specific time period

Indolent: noninvasive or slow growing

Infiltrating ductal carcinoma: the most common type of breast cancer; the cancer begins in the milk ducts and invades other tissues

Inguinal: relating to the groin

Inhibitor: a drug or compound that slows or blocks biological, chemical or enzymatic action

Initiated cell: a cell which has undergone genetic changes leading to cancer after an environmental or chemical insult

In situ cancer: early stage cancer that has not spread

In utero: in the uterus; typically refers to events that occur in the womb before birth

In vitro: in an artificial environment; refers to a process that is studied in a test tube or culture medium

In vivo: studies conducted within a living organism

Insulin: a hormone secreted by the beta cells of the islets of Langerhans of the pancreas; essential for metabolism and regulation of blood sugar; causes liver and muscle cells to take in glucose and store it in the form of glycogen; causes fat cells to take in blood lipids and turn them into triglycerides

Insulin-like growth factor: a hormone, with other growth-promoting factors, that plays a role in the development of the mammary gland; also known as somatomedin

Internal (absorbed) dose: the amount of an environmental agent or chemotherapeutic agent absorbed by the organism and available to undergo metabolism, transport, storage and/or elimination

Indraductal proliferation: a precursor lesion in the DMBA rat model in which only epithelial cells within the ducts are affected

Invasive lobular carcinoma: breast cancer that originates in the milk glands and spreads into surrounding tissues; accounts for 10 to 15 percent of all breast cancers

Ionizing radiation: high energy waves; kills and/or retards cell development and causes gene mutations and chromosome breaks; a known cause of breast cancer

Irradiation: the use of high energy radiation to kill cancer cells

Isoflavones: substances found in soy products that can act as weak estrogens; currently being studied for their prophylactic properties

Isoform: a protein that has the same function as another protein but which is encoded by a different gene and may have small differences in its sequence


Laser capture microdissection: a method for isolating pure cells from specific microscopic regions of tissue sections; useful for collecting selected cells for DNA, RNA and/or protein analyses; does not alter or damage the morphology or chemistry of the collected sample or surrounding cells

Latency: time between exposure to a pathogenic organism, chemical agent or radiation, and the onset of disease

Leptin: a hormone produced by adipose (fat) tissue which has a role in body weight regulation, blood cell development, blood vessel formation and immune function; plays a central role in fat metabolism and helps to control appetite via the brain's hypothalamus

Leukocytes: also called white blood cells; type of cells that fight infection

Limit of detection: the smallest amount (concentration) that can be detected with reasonable certainty using a specific analytical procedure

Linear dose response: a type of response in which the risk of disease changes at the same rate as the exposure; as the exposure increases, the risk disease increases proportionately.

Lipophilic: ability of a chemical compound to dissolve in fats, oils, lipids and nonpolar solvents

Lobular carcinoma in situ: a noncancerous overgrowth of cells in breast lobules; may increase chances for developing breast cancer in the future

Local cancer: a noninvasive cancer that is entirely confined to the original organ

Locally advanced cancer: cancer that has spread to other parts of the breast and nearby lymph nodes

Lymphatic system: tissues and organs that produce, store and carry leukocytes that fight infection; system includes the bone marrow, spleen, thymus, lymph nodes and a network of thin tubules that carry lymph to all the tissues in the body

Lymphomas: cancers that begin in cells of the lymphatic (immune) system; Hodgkin's and non-Hodgkin's are the two major categories of lymphoma


Macrophage: a type of white blood cell that helps remove bacteria, viruses and abnormal cells

Malignant tumor: a cancerous growth that can invade and destroy nearby tissue and spread to other parts of the body

Mammary whole mount preparation: a procedure in which one or more rat mammary gland is removed, defatted, specially stained and mounted for examination; allows for examination of the whole mammary

Mass spectrometry: a laboratory technique for separating ions (atoms or groups of atoms with a positive or negative charge) based on their mass-to-charge ratios; a state of the art analytical technique used to measure biomarkers

Maximum contaminant level: the highest level of a contaminant that U.S. Environmental Protection Agency allows; a legally enforceable standard

Maximum contaminant level goal: the level of a contaminant at which there would be no risk to human health; not a legally enforceable standard

Melanoma: a form of skin cancer that begins in melanocytes (cells that make the pigment melanin); usually begins in a mole

Menarche: the first menstrual period

Metabolic syndrome: a group of metabolic risk factors, including central obesity, blood fat disorders, insulin resistance and high blood pressure.

Metabolism/digestion: a chain of energy-producing chemical reactions in the body; all energy and material transformations that occur within living cells. These processes are the basis of life, allowing cells to grow and reproduce, maintain their structures and respond to their environments.

Metabolite: intermediate or end products of metabolism

Metabolome: the collection of all metabolites in a biological organism; considered the compilation of an organism’s gene expression

Metabolomics: the systematic study of the total metabolite pool (the metabolome) using nuclear magnetic resonance profiling

Metalloproteinases (or metalloproteases): enzymes which use a metal in the catalytic mechanism; some are involved in cancer progression

Metaplasia: abnormal change in cell appearance

Metastases: the spread of cancer from one part of the body to another

Mitogen: a chemical that stimulates cell division/growth

Molecule: is made up of two or more atoms. Biological molecules (such as proteins and DNA) are made up of thousands of atoms

Morphogenesis: differentiation and growth of tissues and organs during development

Morphology: pertaining to the shape and form (structure) of an organ, tissue, etc.

Mortality rate: the number of deaths in a given population over a specified period of time

Multifactorial: referring to multiple factors. Mutifactorial disorders result from mutations in multiple genes and frequently involve exposures to environmental chemicals

Multivariate analysis: analysis of more than one statistical variable at a time; distinguished from univariate analyses

Mutation: an alteration in a gene that can result in a damaged, lost or displaced gene; it can be minor, deleterious or have no effect on cell function


NBCC (National Breast Cancer Coalition): a coalition of grassroots breast cancer organizations that lobby at the national, state and local levels for public policies that impact breast cancer research, diagnosis and treatment; conduct educational programs like Project LEAD, etc.

NCI (National Cancer Institute): one of the National Institutes of Health established in 1937; supports and conducts basic and clinical biomedical research and training addressing cancer-related diagnosis, treatment, prevention and public education

Neoplasia: abnormal (can be benign or cancerous) growth of cells

NIEHS (National Institute of Environmental Health Sciences): one of the National Institutes of Health established in 1969; supports and conducts basic and human research and training addressing how environmental exposures, genetic susceptibility and age interact to affect health and disease

NIH (National Institutes of Health): a part of the U.S. Department of Health and Human Services; the primary federal agency responsible for conducting and supporting medical research; consists of 27 institutes and centers

Nucleus: the most prominent component of a cell containing hereditary information (chromosomes)

Nulliparity: condition of having borne no children


Odds ratio (OR): the ratio of the odds of a condition/event occurring in one group to the odds of it occurring in another group; OR>1 indicates that the event/condition is more likely in the first group; OR<1 indicates that the condition/event is less likely in the first group.

Olestra: a fat substitute that adds no fat, calories or cholesterol to products. It was created by Procter & Gamble in 1968; also known by its brand name, Olean

Omega-3 fatty acids: type of polyunsaturated fatty acids that are derived from food; found in cold-water fish (tuna, salmon and mackerel) and in dark green leafy vegetables, flaxseed oil and some vegetable oils. Capable of reducing serum cholesterol levels. Examples:

  • Docosahexaenoic and eicosapentaenoic acids – in fish.
  • Alpha-linolenic acid – the only omega-3 fatty acid found in vegetable products; most abundant in canola oil

Oncogene: a gene that normally directs cell growth, but becomes altered, thereby promoting cancer growth. Gene alterations can be inherited, occur randomly, or can be caused by an environmental exposure to carcinogens.

Organic pollutants: (See POP.)

Outcome measure: the endpoint being studied; may be be directly quantifiable or surrogate measures may be used as an estimate or index.

Overexpression: excess of a particular protein; can be caused by an increase in the number of copies of the gene being expressed or increasing the binding strength of the promoter region; may be related to cancer progression

Oxidative stress: physiological stress on the body that is caused by the cumulative damage done by free radicals inadequately neutralized by antioxidants. It is associated with aging and cancer development


Paradigm: broadly, a philosophical or theoretical framework of any kind; the theories, laws, evidence and generalizations that are used to formulate research questions and perform experiments

Pathogen: a disease-causing organism

Pathology: the study and diagnosis of disease through examination of organs, tissues, cells and body fluids; the study of disease processes

PBBs (polybrominated biphenyls): industrial chemicals found in plastics used in a variety of consumer products to make them difficult to burn, i.e., used as flame retardants

PCBs (polychlorinated biphenyls): a group of over 200 industrial chemicals that were widely used. In 1974, all PCB production was banned in the U.S., but PCBs continue to be released in the environment and are found in human tissues and breast milk.

Perfluorooctanoic acid: used to manufacture various non-stick consumer products, including Teflon cookware and Gore-Tex clothing

Persistent organics (See POP.)

Pesticide: a chemical used to destroy pests of any sort; the term includes fungicides, herbicides and insecticides

PFC (Perfluorocarbons): a group of human-made chemicals composed of carbon and fluorine only; emitted as byproducts of industrial processes and also used in manufacturing

Phenotype: any observed quality of an organism, such as its morphology, development or behavior; distinguished from genotype

Phthalates: a class of industrial compounds used widely as plastic softeners, additives to perfumes and hairsprays, lubricants and wood finishers, among other things

Physiological: pertaining to the normal vital processes of organisms

Phytoestrogens: naturally occurring compounds found in plants, such as soybeans, or plant products, such as whole grain cereals, that act like weak estrogens in the body

Pipet: a procedure for exact measurement of fluid

Polymorphism: the quality or character of occurring in several different forms; genes can be polymorphic

POP (persistent organic pollutants or pesticides): chemical substances that persist in the environment (do not biodegrade), bioaccumulate in human and animal tissue, biomagnify in food chains and pose risks of causing adverse effects to human health and the environment. POPs released in one part of the world can travel far beyond their source of origin via the atmosphere, oceans and other pathways. Health effects include cancer, damage to the nervous system, reproductive disorders and disruption of the immune system.

Postnatal: occurring after birth

Precocious puberty: the onset of puberty before the age of seven in Caucasian girls and before the age of six in African-American girls

Prevalence: the total number of cases of a disease/condition in a given population at a point in time

PRG (Pink Ribbon Girls): a support network for young breast cancer survivors in Greater Cincinnati

Progesterone: a steroid hormone secreted by the adrenal glands, brain, ovary and placenta; involved in the female menstrual cycle, embryogenesis, pregnancy and gestation; the major naturally occurring human progestogen

Progestin: a synthetic progestogen that has some biological activity similar to progesterone

Prospective study: a research study design that follows a cohort forward in time

Protease: any enzyme that digests proteins by hydrolysis (reaction with water); any enzyme that reacts with water to break the peptide bonds that link amino acids together in the polypeptide chain

Proteins: molecules in the cell that perform a wide variety of functions, such as protection support/movement, transportation, and activation of the chemical reactions that sustain life (e.g., enzymes for digesting food)

Proteomics: the study of the full set of proteins (the proteome) encoded by a genome

Psychosocial: refers to an individual’s psychological development in the context of their social environment. The term can be used to describe the unique internal mental processes that occur within the individual in response to her/his interactions with others such as parents, peers and teachers.

Puberty: a series of biologic events that leads to the attainment of adult stature, maturation of the interaction of the master glands of the endocrine system with the ovaries and testes, and the ability to reproduce

Putative: generally regarded as such, but not definite; for example, putative carcinogen


Receptor: a protein inside or on the surface of the cell, capable of binding to a specific substance (such as hormones) and exert biological actions (cell growth and differentiation); example: estrogen receptor

Reference interval: a range of laboratory values for a specific analyte determined to be normal for specific age and gender categories; provides relevant comparison information for interpreting results; the 95 percent reference interval is most often reported

Refractory cancer: cancer that does not respond to treatment

Relapse: the return of cancer after initial improvement

Relative risk (RR): the ratio of the probability of a condition/event occurring in an exposed group versus the condition/event occurring in the control (nonexposed) group. RR=1 indicates there is no difference; RR>1 indicates the risk is greater among the exposed; and RR<1 indicates the risk is greater among the control.

Risk factor: a characteristic that increases the risk of disease; may be genetic, lifestyle behaviors, diet, environmental exposures, etc.

RNA (riboneucleic acid): “reads” information encoded in DNA and transfers it to a part of the cell that makes functional proteins


Secretion: production of a substance that differs in its chemical and physical properties from the cell or gland that produces the product; intended for use within the organism, not to be excreted; the product can be a solid, liquid or gaseous.

Selenium: a dietary mineral essential for chemical reactions in the brain and other parts of the body

Sensitive subpopulation: people who may be more vulnerable to exposure to an environmental exposure, whether a biological, physical or chemical agent; commonly refers to infants and children, elderly and people with compromised immune systems

Sentinel lymph node: the first lymph node where cancer spreads

Signaling: a complex system of communication that governs basic cellular activities and coordinates cell actions; errors in cellular information processing are responsible for diseases such as cancer, autoimmunity and diabetes. The ability of cells to perceive and correctly respond to their micro-environment is critical to development, tissue repair, immunity and homeostasis.

Somatic mutations: alterations in the DNA that are not transmitted to the offspring; distinguished from germ line mutations which can be transmitted to descendants

Somatomedin: see insulin-like growth factor

Statistical significance: based on probabilities, the observed outcome is unlikely to have occurred by chance alone; statistical evidence of a difference

Stress: disturbance of physiologic equilibrium

Stress hormones: such as cortisol and norepinephrine are released during periods of high stress; the hormone regulating system is known as the endocrine system

Stromal: pertaining to the connective tissue of an organ, gland or other structure

Susceptible/susceptibility: a term used to describe a person(s) who is more likely to develop a disease; at risk of disease


T cell: a type of white blood cell that attacks damaged cells, including cancer cells

Target population: particular group of people selected for study, intervention, education, etc.

Telomerase: an enzyme which mediates the repair or preservation of terminal sequences of chromosomes

Terminal ductal lobular unit (TDLU): alveolar-lobular structure which forms the functional unit of the human breast; changes with hormonal events such as puberty, pregnancy and lactation.

Terminal end buds: structures at the tips of invading primary ducts in the developing mammary gland

Thelarche: the beginning of breast development in the female

Threshold dose response: a type of response in which, at very low exposures, there appears to be no detectable increased risk of disease; there is a threshold below which no risk is detected

Tissue: a group or layer of cells, such as the skin, that together performs specific functions

Titration: a procedure to determine the lowest antibody concentration needed to produce effective staining of given structures with minimal background

Toxicology: the study of the effects of physical and chemical agents on living organisms

Transcriptional: relating to the transfer of genetic information from one kind of nucleic acid to another; for example, from DNA to RNA

Transgenic: referring to an organism in which new DNA has been introduced into the germ (reproductive) cells by injecting it into the nucleus of the ovum

Tumor: an abnormal mass of tissue that results from uncontrolled cell division; can be benign (non-cancerous) or malignant (cancerous)

Tumor suppressor genes: or “cell guardians” – genes whose normal function is to prevent abnormal cells from dividing; certain mutations in tumor suppressor genes lead to cancer


UV: ultraviolet light


Vascular: relating to or including blood vessels; the vascular system includes the arteries, veins and capillaries that carry blood to and from the heart

VEGF (vascular endothelial growth factor): responsible for the growth of blood vessels

Virus: parasitic microorganisms capable of causing disease; smaller than a single cell or bacterium, they cannot reproduce outside a living organism


Water contaminant: anything found in water (including microorganisms, radionuclides, chemicals, minerals, etc.) which may be harmful to human health

  • Inorganic contaminants are mineral-based compounds such as metals, nitrates, and asbestos, which are naturally occurring in some water, but can also enter water through human activities.
  • Organic contaminants are carbon-based chemicals, such as solvents and pesticides, which enter water through cropland runoff, discharge from factories, and other means.

Whole mounts: a preparation in which a sample of tissue (e.g., the entire breast) is examined for structure, type and frequency of lesions and other measurable parameters


Xenobiotic: an environmental compound; outside the body

Xenografts: a type of tissue graft in which the donor and recipient are of different species