THE CHALLENGE OF TNBC
Defining the undefined
WHAT IS TNBC?
Triple Negative Breast Cancer (TNBC) is a relatively rare and aggressive form of breast cancer that disproportionately affects women of African origin. Currently, TNBC is difficult to recognize in patients, it is unresponsive to commonly used targeted therapies, and typically means a poor outlook for the patient.
1. THE CHALLENGE OF TNBC
At the cellular level, many common breast cancers can usually be recognized by one or more of three hormone receptors; TNBC has none of these three biomarkers, hence the “triple negative” moniker. TNBCs are usually poorly differentiated and display high mitotic activity, intratumoral heterogeneity, and pushing borders with geographic necrosis. They typically occur in younger patients than many other breast cancers, and metastasize to distant sites without lymph node involvement.
2. CATEGORIZING TNBC
Knowing that a cancer lacks three common cancer biomarkers is not terribly helpful for categorizing, diagnosing, or treating it, since there are an infinite number of unrecognized possibilities for what it might be. Efforts have been made to categorize TNBCs, but no consensus has yet been reached; in fact ‘TNBC’ seems to represent a motley crew of breast cancer subtypes clubbed together solely by their triple negative status.
3. PROGNOSTICATING AND TREATING TNBC
Just as TNBC is difficult to categorize, it is also difficult to predict patient outcomes: the usual tests have no known biomarkers to look for, and we therefore have very little information to guide prognosis. As a result, all TNBCs are generally classified as being “high risk”, though this is rather unquantifiable. Unlike other breast cancers that express hormone and/or HER2 receptors, triple negative breast cancers are unresponsive to common hormone-based and HER2-targeting therapies. This leaves only cytotoxic chemotherapies, which poorly discriminate between malignant and non-malignant cells and cause devastating side effects.
4. THE FUTURE
Despite the challenges of TNBC, there is plenty to be hopeful about. Indeed, our currently limited knowledge means there are many exciting possibilities to uncover new knowledge, and that’s why ICART was formed: to bring together the best minds in diverse aspects of TNBC research to do more in partnership than we can as individual groups.