Racial and ethnic disparities in breast cancer mortality appear to be the cause of complex biological and socioeconomic factors.
In 2020, breast cancer cases surpassed lung cancer among women, making breast cancer the most common cancer among women globally. Despite increases in the breast cancer incidence rate, mortality due to breast cancer has consistently declined since 1989. However, although these advances have decreased mortality in general, African American women remain 40% more likely to die from breast cancer when compared to White women. This study, published in Cancer Reports, provides an overview of the tumor microenvironment and immune-based treatment options for triple-negative breast cancer, and their potential for decreasing health disparities related to race.
Racial Breast Cancer Mortality Disparities Have Many Causes
The racial disparities between White and Black women with breast cancer are the result of multifactorial etiology. Black women have a disproportionate incidence rate of triple-negative breast cancer, which has a poor prognosis and limited treatment options in general. Additionally, the tumor microenvironment is seen as increasingly relevant when it comes to understanding tumor progression, metastasis, and treatment options in this population.
The tumor microenvironment of Black women shows various cellular and acellular differences that are associated with pro-tumorigenic effects. These include increased levels of adipocyte-related hormone, resistin, IL-6, and the chemokine CCL2, which can give rise to an increased density of M2 macrophages. Additional factors such as elevated vascular endothelial growth factor in the tumor microenvironment in Black women can increase vascular density, which can facilitate aggressive tumor growth. A pro-tumorigenic microenvironment is supported by increased levels of CXCL12, a member of the CXC chemokine subfamily, which can result in an increase in regulatory T lymphocytes.
Tracking the Tumor Microenvironment May Be the Key to Effective Treatment
The authors conclude by noting that additional research support that targets these questions, in particular the treatment of triple-negative breast cancer, is essential to help provide this population with better outcomes. Because this is a multifactorial issue, a better understanding of how each factor contributes to the tumor microenvironment is essential in future research. The importance of social and economic contributions is important, as well.
Zajac, K. K., Malla, S., Babu, R. J., Raman, D., & Tiwari, A. K. (2023). Ethnic disparities in the immune microenvironment of triple negative breast cancer and its role in therapeutic outcomes. Cancer Rep (Hoboken), e1779. https://doi.org/10.1002/cnr2.1779