You may have heard a breast cancer survivor talk about what type of breast cancer they were diagnosed with. There are many types, and they are differentiated by the type of cells that develop into cancer. Here are a few terms and types of breast cancer you may have heard of:
Carcinomas and adenocarcinomas
Carcinomas start in the epithelial cells, which are cells that line organs and tissues in the body. Most breast cancers form in epithelial cells. Adenocarcinomas are a more specific type of carcinoma that starts in the cells of the milk ducts or lobules, which are the glands that make milk.
Ductal carcinoma - breast cancer that starts in the milk ducts.
Ductal carcinoma in situ (DCIS) – a pre-cancer in a milk duct that has not spread to the breast tissue, also known as intraductal carcinoma or stage 0. DCIS is one of the more curable breast cancers and makes up 1 in 5 new breast cancer diagnoses.
Lobular carcinoma – breast cancer that starts in the milk glands.
Invasive – breast cancer that has spread into surrounding tissue, also known as infiltrating. Two types of invasive breast cancer are invasive ductal carcinoma (IDL) and invasive lobular carcinoma (ILC). Between 70% and 80% of breast cancers are IDL.
Triple-negative breast cancer (TNBC) – a type of invasive breast cancer where the cancer cells do not have estrogen (ER) or progesterone receptors (PR). The cancer cells also either don’t make the HER2 protein at all or the cells make too much of HER2. TNBC is aggressive and more commonly diagnosed in women younger than 40. Around 10%-15% of breast cancer cases are TNBC.
Inflammatory breast cancer (IBC) – a rare invasive breast cancer where cancer cells block lymph vessels in the skin. The blockage causes inflammation in the breast, including swelling and redness. IBC only makes up about 1%-5% of breast cancers.
HER2 – a protein that aids in the rapid growth of cancer cells. HER2 can be positive and negative. HER2-positive breast cancer means the cancer cells have higher than normal levels of HER2. HER2-positive breast cancer grows faster than HER2-negative breast cancer. Invasive breast cancers are tested for HER2. Around 15%-20% of breast cancers have high levels of HER2.
Genetic Breast Cancer
Contrary to popular belief, only about 5%-10% of breast cancers are genetic. In this case, those with hereditary breast cancer received mutated genes from a parent.
Here are gene mutations that are related to breast cancer development:
BRCA1 and BRCA2 – the most common causes of inherited breast cancer. Usually, these genes help repair damaged DNA, but the mutated versions may result in abnormal cell growth, which we know can lead to cancer. Those with a BRCA1 or BRCA2 mutated gene inherited from a parent are at a higher risk of developing breast cancer, are more likely to be diagnosed at a younger age, and are more likely to develop ovarian and other cancers.
ATM, PALB2, TP53, CHEK2, PTEN, CDH1, and STK11 are less common gene mutations that can also lead to breast cancer.
If you know of a first-degree relative who has had breast cancer, it is important to speak to your provider about your risk and seek genetic testing. Karmanos offers genetic testing and counseling throughout the Karmanos Cancer Network within McLaren Health Care to help people understand their risk of developing cancer. Genetic counseling is also available to assist patients with a prevention and screening plan. Genetic testing does not require a physician referral, although some insurance companies may require that a provider refer you. Learn more about the Karmanos Genetic Counseling Service here.
Visit the American Cancer Society’s website for more information on additional terms and types of breast cancer.
Karmanos Cancer Institute and McLaren Health Care hospitals provide experts in treating all types of breast cancer. Early detection of breast cancer is important because the disease is most treatable in the early stages. Karmanos and McLaren recommend an annual screening mammogram beginning at age 40. Women with one or more risk factors for breast cancer should talk with a provider about when to start getting mammograms. To schedule your mammogram at a Karmanos or McLaren location near you, visit karmanos.org/digitalmamm.
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