TNBC

Most women receive some type of additional therapy after surgery to remove a cancerous tumor (lumpectomy or mastectomy). The type of additional therapy they receive depends, in part, on the type of breast cancer they have. Every cell in the human body has receptors-think of them as tiny doors into a cell. Once unlocked, scientists can discover the secrets of the cell: how to turn it on, turn it off, or kill it if it becomes cancerous. When treating most types of breast cancer in the United States, scientists are able to unlock-and combat-these breast cancer cells with highly effective drugs such as tamoxifen or herceptin. Triple negative breast cancer (TNBC) tumor cells earned their name because they do not have receptors for estrogen, progesterone or human epidermal growth factor receptor 2, the three types of tiny doors scientists have been able to unlock. Therefore they are "negative" to these three types and do not respond to the powerful breast cancer treatments developed to target these receptors. Less is known about drug therapies for TNBC because it is not the most common type of breast cancer diagnosed in the United States and Europe, where most of the research has been done.  [1]

Even though we commonly refer to breast cancer as one disease, women battling Triple Negative Breast Cancer (TNBC) should consider it and their treatment options unique because TNBC is only one type of cancer among many.  Although TNBC can affect women of all ethnic groups, it disproportionately affects young African American women.  Nearly 40% of young African-American and Hispanic women diagnosed with breast cancer have TNBC, compared to only 15% of young women from other ethnic groups.  

Because TNBC doesn't respond to targeted drug therapies, the strategy of choice is chemotherapy, sometimes followed by radiation. "There have been more advances in chemotherapy for this type of breast cancer than others," says Lisa Carey, M.D., a breast cancer specialist, University of North Carolina Lineberger Comprehensive Cancer Center. Be Proactive to Prevent TNBC.  Live healthy and you up your chances of avoiding TNBC. Yet should it strike, fighting back and winning means being an active, involved patient. [1]

History of Triple Negative Breast Tumors

"Triple negative" is a term that has only begun to be widely used in the last few years.  In the mid-1980s, when it became apparent that hormone therapies only worked in tumors that were estrogen receptor (ER)-positive or progesterone receptor (PR)-positive, pathologists began to routinely test all breast tumors for their hormone status. As a result, for the past two decades, breast cancer patients have been divided into two categories: those who could benefit from hormone therapy and those who would not.

This categorization began to change in 1998, when the FDA approved the use of Herceptin for women with metastatic breast cancer that overproduces a protein called HER2. From that point on, all women with metastatic disease also had their tumors tested for their HER2 status. The biggest change, though, occurred in 2006, when the FDA approved the use of Herceptin in the adjuvant setting (after surgery) to reduce the risk of recurrence. With this development, pathologists began to test all tumors for their HER2 status in addition to their ER and PR status.

Gradually, over the few years, instead of describing a tumor as ER negative, PR-negative, and HER2-negative, the shorthand term "triple negative" became popular.  This also resulted in a number of news stories about this "new" type of cancer. But it wasn't really new. It's just the use of Herceptin in the adjuvant setting led us to start thinking about these tumors in a new way.

Testing all women with early stage disease for all three receptors allowed us to learn that African-American women appear more likely to develop triple-negative tumors than women of other ethnic backgrounds. We've also found that women who carry a BRCA1 mutation typically develop these types of tumors as well. We don't yet know the biological reasons for this, but scientists are studying African-American women and women with BRCA1 mutations in an attempt to learn why. [2]

REFERENCES
[1] Triple Threat: How to fight the breast cancerdis proportionately affecting young Black women Sheree Crute and Lynya Floyd Originally Published in the October 2008 issue of Essence magazine, pg 179
[2] Berry DA, Cirrincione C, Henderson IC, et al. Estrogen-Receptor Status and Outcomes of Modern Chemotherapy for Patients with Node-Positive Breast Cancer. Journal of the American Medical Association 2006 Apr 12; 295(14):1658–67

Last Medical Review: August 2010