Articles on Breast Cancer
What is HER2-positive breast cancer?

HER2 (human epidermal growth factor receptor 2) is a transmembrane tyrosine kinase receptor and is expressed by, and involved in the growth of, some cancer cells. For example, HER2 is overexpressed in 18% to 20% of invasive breast cancers and affects treatment as well as prognosis of breast cancers.
- In about 10%-20% of breast cancers, the cancer cells test positive for HER2, sometimes referred to as the HER2/neu protein.
- HER2 is a growth-promoting protein located on the surface of some cancer cells.
- HER2-positive breast cancers tend to grow more rapidly and spread more aggressively than breast cancers that are HER2-negative.
What causes HER2-positive breast cancer?
Doctors do not know what specifically causes some breast cancers to express this protein while others do not.
What tests detect HER2?
All patients with invasive breast cancer should have their tumor cells tested for HER2. Medical professionals routinely perform this test in the pathology laboratory at the time of diagnosis, using the sample of your breast tissue removed for diagnosis. The testing for HER2 can involve one or more of the following tests.
Health care professionals may use either immunohistochemistry (IHC) to identify the HER2 protein or in-situ hybridization (ISH) testing to look for the gene.
- IHC test: This test shows if there is too much HER2 protein in the cancer cells and is graded 0 to 3.
- FISH test: This test evaluates if there are too many copies of the HER2 gene in the cancer cells. This test is either positive or negative.
- SPoT-Light HER2 CISH test: This test also evaluates if there are too many copies of the HER2 gene in the cancer cells and is reported as positive or negative.
- Inform HER2 Dual ISH test: This test also evaluates if there are too many copies of the HER2 gene in the cancer cells and is reported as positive or negative.
Do symptoms and signs of HER2-positive breast cancer differ from those of HER2-negative breast cancer?
The signs and symptoms for HER2-positive breast cancers are the same as for HER2-negative breast cancers, except for the fact that HER2-positive cancers are likely to grow faster and are more likely to spread. The following are possible signs of breast cancer:
- Thickening or lump in the breast that feels different from the surrounding area
- Inverting of the nipple
- Nipple discharge or redness
- Breast or nipple pain
- Swelling in your armpit or collarbone could mean breast cancer has spread to lymph nodes in that area
- Swelling of part of the breast
- Redness
- Changes in the skin of the breast
- Skin dimpling (peau d'orange)
- Lymph node changes

QUESTION
A lump in the breast is almost always cancer. See AnswerWhat is the treatment for HER2-positive breast cancer?
Your health care team needs to evaluate all therapy and provide guidance in response to all test results available and the specific circumstances of your cancer. Treatment for HER2-positive breast cancer typically involves a combination of chemotherapy and specific drugs used for cancers expressing the HER2 protein:
- Trastuzumab (Herceptin): This is a monoclonal antibody against HER2, as well as the first drug developed that targets the HER2 protein.
- Pertuzumab (Perjeta): This is another monoclonal antibody that targets HER2-positive cancers.
- Ado-trastuzumab emtansine or TDM-1 (Kadcyla): It's a monoclonal antibody that is attached to a chemotherapy drug, emtansine.
- Lapatinib (Tykerb): Medical professionals usually use this kinase inhibitor with chemotherapy or hormone therapy.
- Neratinib (Nerlynx) interferes with the cancer cells' ability to respond to growth signals.
What is the outlook (prognosis) for HER2-positive breast cancer?
As mentioned before, HER2-positive breast cancers are more likely to grow faster and to come back after treatment than cancers that are HER2-negative. However, the development of the drugs discussed above that specifically treat cancers expressing HER2 has led to significant improvements in the outlook for people with HER2-positive breast cancer. While survival rate statistics for breast cancer are not broken down to show rates for HER2-positive cancers, the 5-year survival rate for all localized breast cancers is 99%. However, the 5-year survival rate for metastatic breast cancer is 27%, so it is important to treat HER2-positive breast cancer as early as possible to reduce or prevent spread.
Latest Cancer News
Daily Health News
Trending on MedicineNet
Health Solutions From Our Sponsors
Salerno, K.E. "NCCN Guidelines Update: Evolving Radiation Therapy Recommendations for Breast Cancer." J Natl Compr Canc Netw 15(5S) May 2017: 682-684.
Shield, Kevin D., et al. "Alcohol Use and Breast Cancer: A Critical Review." Alcoholism: Clinical and Experimental Research Apr. 30, 2016.
Top Breast Cancer/Her2Positive Related Articles
Breast Cancer
Breast cancer is an invasive tumor that develops in the mammary gland. Breast cancer is detected via mammograms, breast self-examination (BSE), biopsy, and specialized testing on breast cancer tissue. Treatment of breast cancer may involve surgery, radiation, hormone therapy, chemotherapy, and targeted therapy. Breast cancer risk may be lowered by managing controllable risk factors.
What you should know about breast cancer
- Breast cancer is the most common cancer among American women.
- One in every eight women in the United States develops breast cancer.
- There are many types of breast cancer that differ in their capability of spreading (metastasize) to other body tissues.
- The causes of breast cancer are unknown, although medical professionals have identified a number of risk factors.
- There are many different types of breast cancer.
- Breast cancer symptoms and signs include
- a lump in the breast or armpit,
- bloody nipple discharge,
- inverted nipple,
- orange-peel texture or dimpling of the breast's skin (peau d'orange),
- breast pain or sore nipple,
- swollen lymph nodes in the neck or armpit, and
- a change in the size or shape of the breast or nipple.
- Breast cancer can also be symptom free, which makes following national screening recommendations an important practice.
- Breast cancer is diagnosed during a physical exam, by a self-exam of the breasts, mammography, ultrasound testing, and biopsy.
- Treatment of breast cancer depends on the type of cancer and its stage (0-IV) and may involve surgery, radiation, or chemotherapy.
Breast Cancer Recurrence
Breast cancer most often recurs within the first three to five years after the initial treatment. Changes in the look, feel, or appearance of the breast may indicate breast cancer recurrence. Factors related to recurrence include tumor size, tumor grade, hormone receptor status, lymph node involvement, and oncogene expression. Treatment for recurrent breast cancer depends on the initial treatment.Breast Cancer Facts
Breast cancer is the most common non-skin cancer of American women, but it can also occur in men. Every year in the U.S., there are over 266,000 new diagnoses of breast cancer. A woman has a risk of one in eight for developing breast cancer at some point during her lifetime.
Breast Cancer Stages
Breast cancer staging is the determination of the extent and spread of the cancer. An individual's health care team uses stages to summarize the extent of the cancer in a standardized way that is recognized by all health care providers. They use this staging to determine the treatment most appropriate for the type of cancer. Cancer staging helps to determine the prognosis, or outlook, of a cancer, including rates of recurrence and survival rates.Can Fibroadenomas Turn Into Breast Cancer?
A fibroadenoma is the most common type of benign, non-cancerous lump of the breast. Although it is rare, complex fibroadenomas and phyllodes tumors have a chance to develop into malignant breast cancer.Inflammatory Breast Cancer
Inflammatory breast cancer is an accelerated form of breast cancer that is not usually detected by mammogram or ultrasound. Symptoms of inflammatory breast cancer include pain in the breast, skin change in the breast area, bruise on the breast,sudden swelling of the breast, nipple retraction or discharge, and swelling of the lymph nodes.Male Breast Cancer
Male breast cancer accounts for 1% of all breast cancers, and most cases are found in men between the ages of 60 and 70. A man's risk of developing breast cancer is one in 1,000. Signs and symptoms include a firm mass located below the nipple and skin changes around the nipple, including puckering, redness or scaling, retraction and ulceration of the nipple. Treatment depends upon staging and the health of the patient.What Is the Difference Between a Radical Mastectomy and Modified Radical Mastectomy?
In a radical mastectomy, the entire breast tissue along with the nipple, covering skin, lymph nodes (filter organs for harmful substances) in the armpit and chest wall muscle under the breast is removed. It is known as a standard treatment for breast cancer. In a modified radical mastectomy (MRM), the entire breast is removed, including the skin, areola (surrounding the nipple), nipple and most armpit lymph nodes. The underlying chest wall muscles (the pecs) will be left intact. Additionally, the skin covering the chest wall may or may not be removed.Triple-Negative Breast Cancer
Triple-negative breast cancer is more common in Hispanic and African-American women. Signs and symptoms include a lump in the armpit or breast, nipple discharge and inversion, and changes in the breast's skin. Treatment may incorporate surgery, chemotherapy, and radiation therapy.What Is Usually the First Sign of Breast Cancer?
A lump in the breast or in the armpits is often the first sign of breast cancer. This may be felt while in the shower. There may or may not be changes in the structure of the breast. Other early signs include changes in breast skin, breast pain and others.