What is TNBC


The diagnosis of a triple negative breast cancer is usually simple. It all starts when a man or a woman feels a lump in the breast. Sometimes it’s the gynecologist or primary care physician that finds it on a routine exam. Other times, the lump can’t be felt at all and is seen on a mammogram or ultrasound (sonogram). Once it is detected by any means, the patient is referred to a breast surgeon for evaluation and a biopsy will be performed. The biopsy should always be a, “minimally invasive biopsy” as opposed to taking the patient to the operating room and removing it surgically. There are three types of minimally invasive biopsies:


Estrogen and Progesterone receptors are normal proteins that exist on the surface of all breast cells. Some breast cancers maintain their ability to make the receptors and some cancers loose that ability. If the cancer does not express those receptors on the surface of its cells and has therefore lost the ability to make those receptors it is Estrogen and Progesterone receptor negative (ER, PR negative).


Triple negative breast cancer is most frequent in African American women. Roughly 40% of breast cancers in African American women are triple negative compared to roughly 15% in Caucasian women. Another difference in African-American women who get triple negative breast cancer is that most of them are pre-menopausal.  One other demographic group that is prone to have triple negative breast cancer are women who have BRCA1 mutations.


The association between BRCA1 mutations and triple negative breast cancers has led to research looking for a genetic predisposition to develop these types of cancers. Studies have identified specific locations within genes that appear to be abnormal in a higher proportion of cases than in other types of breast cancer. However, other than the BRCA1 gene, a specific gene causing this type of cancer has not been identified. It is likely that a combination of genetic factors located in specific locations within the genome interactively play a role in the development of TNBC. Genetics is an active field of investigation in TNBC.


Although much is written about the inferior prognosis of triple negative breast cancers compared to other types of cancer, it's important to keep in mind that stage for stage, their prognosis is still fairly similar to the other sub-types. Part of the reason has to do with the fact that hormone blocking agents are not effective due to the lack of estrogen and progesterone receptors.


It is true that Triple Negative Breast Cancer (TNBC) affects young patients, may have a slightly more aggressive behavior than other types of breast cancer and has no option for hormonal manipulation. You may read many gloom and doom posts and publications about the disease.