Glossary

Adenocarcinoma - cancer that starts in the glandular tissue, such as in the ducts or lobules of the breast.

Archived Tumor Sample - tumor sample that has been preserved and stored.

Biopsy - the removal of a sample of tissue to see whether cancer cells are present.  

Chemotherapy - treatment with drugs to destroy cancer cells.  Chemotherapy is often used with surgery or radiation to treat cancer when the cancer has spread, when it has come back (recurred), or when there is a strong chance that it could recur.

Core Biopsy – see needle biopsy.

Diagnosis - identifying a disease from its signs and symptoms and the results of imaging and/or laboratory tests.

Distant Recurrence - cancer that returns in other organs (i.e. lungs, liver, bones) after treatment.

Dysfunctional Estrogen Signaling - Estrogen binds to estrogen receptors, which then activate or inhibit the expression of many “estrogen-responsive” target genes regulating cell growth. Dysfunctional estrogen signaling occurs when certain estrogen target genes lose their “responsiveness” to estrogen, resulting in their abnormal expression.

Early Stage Breast Cancer - Stage I and II, lymph node-negative breast cancer.

Endocrine Therapy - manipulation of hormones to treat a disease or condition. (i.e. Tamoxifen)

Estrogen - a female sex hormone produced mainly by the ovaries.  Estrogen stimulates growth in normal breast cells and some breast cancers.

Estrogen Receptor (ER) – receptors on breast cancer cells to which estrogen can attach and transmit signals that instruct the cancer cells to grow and multiply.  Estrogen receptors are molecules that function as "welcome mats" for estrogen circulating in the blood. Breast cancer cells without these receptors (called estrogen receptor negative or ER-negative) are unlikely to respond to hormonal therapy such as tamoxifen. Cancers with estrogen receptors (ER-positive) are more likely to respond to hormonal therapy.

ER (Estrogen Receptor) Assay - a lab test done on a sample of the cancer to see whether estrogen receptors are present.   

Gene - a segment of DNA that contains information on hereditary characteristics such as hair color, eye color, and height, as well as susceptibility to certain diseases.

Gene Expression - conversion of information encoded in a gene into structures operating in a cell.  The process initiates with gene information encoded first into messenger RNA and then to a protein.

Gene Expression Profile - A picture of the expression of multiple genes from a single specimen.

In Situ (carcinoma in situ) - Pre-cancerous cells that are isolated in the lobes or milk ducts of the breast.

Lumpectomy - surgical procedure to remove a localized mass of tissue, which includes a breast cancer tumor and small amount of surrounding tissue.

Mastectomy - surgical procedure to remove all or part of the breast.

Metastatic – a way to describe cancer that has spread from the primary site (i.e. breast) to other structures or organs, nearby or far away (distant).  

Molecular Tumor Grade Signatures - characteristic gene expression patterns of tumors of different grades (I vs. III) (see tumor grade), which are determined by gene expression profiling technologies such as real-time quantitative PCR.

Node-Negative Breast Cancer - Breast cancer that has not spread to the axillary lymph nodes under the arms.

Node-Positive Breast Cancer - Breast cancer that has spread to the axillary lymph nodes under the arms.

Oncogenetic – promotion of cell growth and multiplication by oncogenes.  These genes are normally present in all cells.  But, oncogenes may undergo changes that activate them, causing cells to grow too quickly and form tumors.

Progesterone – a female steroid sex hormone made by the body that plays a role in the menstrual cycle and pregnancy.

Progesterone Receptor - A protein found inside the cells of the female reproductive tissue, some other types of tissue, and some cancer cells. The hormone progesterone will bind to the receptors inside the cells and may cause the cells to grow.

Progesterone Receptor Assay - A lab test to find out if cancer cells have progesterone receptors (proteins to which the hormone progesterone will bind). If the cells have progesterone receptors, they may need progesterone to grow, and this can affect how the cancer is treated.

Recurrence - the return of cancer after treatment. Local recurrence means that the cancer has come back at the same place as the original cancer. Regional recurrence means that the cancer has come back after treatment in the lymph nodes near the primary site. Distant recurrence is when cancer metastasizes after treatment to distant organs or tissues (such as the lungs, liver, bone marrow, or brain). See also primary site, metastasis, metastasize

Staging - classification system for breast cancers based on three factors; 1) size of the tumor 2) whether the cancer has spread to the lymph nodes, and 3) whether the cancer has spread to other sites in the body (metastasis).

Tumor - an uncontrolled, abnormal, circumscribed growth of cells.   A tumor can be benign (non-cancerous) or malignant (cancerous).

Tumor Grade - Reflects how abnormal a tumor’s cells look under a microscope.  Grading systems divide cancers into the most abnormal (grade 3, poorly differentiated), the least abnormal (grade 1, well differentiated) and those in between (grade 2, moderately differentiated). The pathologist who looks at the specimen assigns the grade. Higher-grade cancers tend to grow and spread faster, and have a worse outlook. Along with the cancer's stage, the grade is used to choose the best treatment.

Tumorigenesis – production or development of tumors.

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