Abnormal cells: Cells that do not look or act like the healthy cells of the body.
Aggressive cancer cells: Cells that are fast growing and have a tendency to spread beyond the area where they started.
Atypical ductal hyperplasia: Abnormal cells that have accumulated in a breast duct. The cells have increased in number and fill almost the entire duct. The cells can keep changing until they become
DCIS. Atypical ductal hyperplasia can increase the risk of a future breast cancer.
Atypical lobular hyperplasia: Abnormal cells that have accumulated in a breast lobule. The cells have increased in number and fill almost the entire lobule. It’s possible for the cells to keep changing until they become LCIS. Atypical lobular hyperplasia can increase the risk of a future breast cancer.
Axillary lymph nodes: Lymph nodes under your arms.
Basal-like breast cancer: Basal-like is one of the four main molecular subtypes of breast cancer. Basal-like breast cancer is hormone-receptor negative and HER2-negative. Also called triple-negative breast cancer.
Benign: Not cancerous or precancerous.
Biopsy: An operation to remove tissue to check whether it’s cancer or not.
BRCA1: An abnormal gene, known as Breast Cancer gene 1, associated with a higher risk of developing breast cancer.
BRCA2: An abnormal gene, known as Breast Cancer gene 2, associated with a higher risk of developing breast cancer.
Clean margins: Removed breast tissue around the tumor in which the outer edge is free of cancer cells. Also called “negative margins.”
Close margins: Removed breast tissue around the tumor in which cancer cells come near the outer edge.
Colloid (mucinous) carcinoma of the breast: A rare type of invasive breast cancer that contains small pools of mucous material.
Comedo DCIS: A type of non-invasive cancer that tends to grow quickly. Comedo refers to areas of dead cancer cells that build up inside the tumor—a sign that the cancer cells are growing so quickly that some of the cells are not getting enough nourishment.
Comedonecrosis: Clumps of dead cancer cells, often seen in high-grade DCIS. The cells are so crowded that some of them do not get enough nourishment and die.
Cribriform carcinoma of the breast: A less common type of invasive breast cancer that invades the connective tissues of the breast and features holes between the cancer cells (like the holes in Swiss cheese).
Cribriform DCIS: A type of non-invasive breast cancer that usually grows slowly. Cribriform DCIS features gaps between cancer cells in the affected ducts (like the pattern of holes in Swiss cheese).
Ductal Carcinoma In Situ (DCIS): An uncontrolled growth of breast cells within the milk duct without invasion into the normal surrounding breast tissue.
EGFR gene: A gene that controls how quickly cells divide. Also called HER1.
EGFR-negative: A breast cancer with a normal number of the EGFR gene.
EGRF-positive: A breast cancer with too many copies of the EGFR gene.
ER-negative: A cancer that does not have estrogen receptors.
ER-positive: A cancer that has estrogen receptors.
Estrogen: The major female sex hormone. Estrogen can cause some cancers to grow.
Extracapsular extension: When cancer has spread outside the wall of a lymph node.
Fibrocystic changes: Benign changes in the breast, such as large amounts of rubbery, firm (“fibrous”) tissue or fluid filled cysts.
FISH (Fluorescence In Situ Hybridization) test: A test for multiple genes, including the HER2 gene.
Gene: The code material for a cell to make a single protein. Proteins perform different functions for the cell including growth and repair.
Genomic assay: A test that analyzes the activity of a group of genes.
Grade: How different the cancer cells look from normal cells as well as how quickly the cells are growing.
Gross lymph node involvement: A situation in which many cancer cells are found in a lymph node.
HER2 (Human Epidermal growth factor Receptor 2): A gene that helps control the growth and repair of cells.
HER2-enriched: One of the four main molecular subtypes of breast cancer. HER2-enriched breast cancer is hormone-receptor-negative and HER2-positive.
HER2 gene amplification: A situation that arises when a HER2 gene doesn’t work correctly and makes too many copies of itself.
HER2-negative: A breast cancer with a normal number of HER2 genes and protein receptors.
HER2-positive: A breast cancer with HER2 gene amplification or HER2 protein overexpression. HER2-positive breast cancers tend to grow faster and are more likely to spread and come back compared to HER2-negative breast cancers.
HER2 protein overexpression: When the HER2 gene makes too many copies of itself, and those extra HER2 genes tell breast cells to make too many HER2 receptors.
HER2 receptors: Proteins made by the HER2 gene that receive signals that stimulate cells to grow and multiply.
Hormone receptors: Proteins on and in cells that respond to signals from hormones.
IHC (ImmunoHistoChemistry) test: A test used to measure proteins, including the HER2 protein.
In situ: A cancer within the part of the breast where it started, such as in the ducts, without signs of spread.
Infiltrating: A cancer that has spread beyond the place where it started. Also called “invasive.”
Inflammatory Breast Cancer (IBC): A rare and aggressive form of breast cancer that starts with reddening, swelling, and warmth of the breast, with symptoms worsening within days or hours. IBC is considered at least stage IIIB.
Inform HER2 Dual ISH test: A test used to figure out whether breast cancer cells are HER2-positive.
Invasive: A cancer that has spread beyond the place where it started. Also called “infiltrating.”
Invasive Ductal Carcinoma (IDC): A cancer that started in the milk duct but has grown into the normal breast tissue around it.
Invasive Lobular Carcinoma (ILC): A cancer that started in the milk lobules and has grown into the normal breast tissue around it.
Ki-67 test: A test that shows how fast cancer is growing.
Lobular Carcinoma In Situ (LCIS): Cells that are not normal but stay inside the milk-making parts of the breast (lobules). LCIS isn’t a true cancer, but a warning sign of an increased risk for developing an invasive cancer in the future in either breast.
Local recurrence: A breast cancer that comes back in the breast area where it was originally diagnosed.
Locoregional recurrence: A breast cancer that comes back in the lymph nodes in the armpit or collarbone area near where the cancer was originally diagnosed. Sometimes referred to as “regional” recurrence.
Luminal A breast cancer: One of the four main molecular subtypes of breast cancer. Luminal A breast cancer is hormone receptor-positive (either estrogen- and/or progesterone-positive) and HER2-negative.
Luminal B breast cancer: One of the four main molecular subtypes of breast cancer. Luminal B breast cancer is hormone receptor-positive (either estrogen- and/or progesterone-receptor-positive) and HER2-positive.
Lymph channels: Vessels that drain clear, cell-cleansing fluid (“lymph”) away from tissues.
Lymph nodes: Filters along the lymph fluid channels they can catch and trap cancer cells before they reach other parts of the body.
Lymph system: A network of vessels and nodes that creates and drains clear, cell-cleansing fluid (“lymph”) from the body. The lymph system is an important part of the body’s immune system.
Lymphatic invasion: When cancer cells are found in the lymph channels.
MammaPrint: A test that analyzes 70 genes from an early-stage breast cancer tissue sample to find out whether breast cancer has a low or high risk of coming back within 10 years after diagnosis.
Mammostrat: A test that measures the levels of five genes in early-stage, hormone-receptor-positive breast cancer cells. A risk index score is then calculated the higher the score, the more likely the cancer is to come back (recur).
Margin: The layer of healthy breast tissue around the cancer that was removed during surgery.
Medullary carcinoma of the breast: A rare type of invasive cancer that usually presents with a soft, fleshy tumor that resembles a part of the brain called the medulla. Medullary carcinoma of the breast is usually hormone-receptor negative and HER2-negative.
Menopause: The time when a woman completely stops getting her period (menstruating).
Metastatic: Breast cancer that has spread to other parts of the body, such as the bones or brain.
Microscopic invasion: A situation in which cancer cells have just started to invade the tissue outside the lining of a duct or lobule.
Microscopic lymph node involvement: When only a small number of cancer cells are found in a lymph node.
Milk ducts: Tiny tubes in the breast that carry milk from the lobules to the nipple.
Milk lobules: Milk-making glands in the breast.
Moderately differentiated: Cancer cells that don’t look like normal cells. They grow a little faster than normal. Also called “grade 2.”
Mucinous (colloid) carcinoma of the breast: A rare type of invasive cancer that contains small pools of mucous material.
Negative margins: Removed breast tissue around the tumor in which the outer edge is free of cancer cells. Also called “clean margins.”
Non-invasive: A cancer that stays inside the part of the breast where it started.
Oncotype DX: A test that provides information on how likely the breast cancer is to return and whether you are likely to benefit from chemotherapy. Oncotype DX can also determine whether someone with DCIS can benefit from radiation therapy.
Papillary carcinoma of the breast: A rare type of invasive breast cancer that is made up of small, finger-like projections.
Papillary DCIS: A type of non-invasive breast cancer that does not spread and tends to grow slowly. Papillary DCIS features cancer cells arranged in a finger-like pattern within the ducts.
Pathologist: A doctor who looks at tissue under a microscope to see if it’s normal or affected by disease.
Pathology report: The written results of each test done on tissue after it has been removed from the body during biopsy, lumpectomy, or mastectomy.
Perimenopause: The 1- to 3-year period of hormonal flux before periods stop completely.
Poorly differentiated: Cancer cells that look very different from normal cells. They are fast growing. Also called “grade 3.”
Positive margins: A situation in which cancer cells come up to the outer edge of the breast tissue that was removed during surgery. This suggests that more cancer cells were left behind in the body.
PR-negative: A cancer that does not have progesterone receptors.
PR-positive: A cancer that has progesterone receptors.
Pre-cancerous: An overgrowth of abnormal cells that shows no signs of invasion. Pre-cancerous cells are a warning sign of possibly developing cancer in the future.
Progesterone: A female sex hormone. Progesterone can cause some cancers to grow.
Prognosis: The most likely outcome of a disease.
Recurrence: When a cancer comes back.
Regional recurrence: A breast cancer that comes back in the lymph nodes in the armpit or collarbone area near where the cancer was originally diagnosed. Sometimes referred to as “locoregional” recurrence.
S-phase fraction test: A test that shows how fast a cancer is growing.
Sclerosing adenosis: A benign breast condition in which enlarged lobules form breast lumps.
Sentinel lymph node: The first lymph node or nodes to which cancer cells are likely to spread from a tumor.
Solid DCIS: A type of non-invasive breast cancer it tends to grow slowly. Solid DCIS cancer cells completely fill the affected breast ducts.
SPoT-Light HER2 CISH test: A test used to count the number of copies of the HER2 gene.
Staging: A system doctors use to classify a breast cancer according to how advanced it is.
Triple-negative breast cancer: Breast cancer that tests negative for estrogen receptors, progesterone receptors, and HER2. Triple-negative breast cancer tends to be more aggressive than other types of breast cancer.
Tubular carcinoma of the breast: A rare type of invasive breast cancer that is made up of tube-shaped cells and tends to grow slowly.
Vascular invasion: When cancer cells are found in the blood vessels.
Well differentiated: Cancer cells that look a little bit different from normal cells. They are usually slow growing. Also called “grade 1.”