HR-positive/HER-negative breast cancer is the most common breast cancer diagnosis. Although it occurs more frequently in white women, women of color experience disparities related to diagnosis, treatment outcomes, and breast cancer mortality.

Breast cancer is cancer that develops in the various tissues and structures of the breast. It can occur in anyone but is most common among people assigned female at birth.

The type of breast cancer a person is diagnosed with depends on its molecular makeup — the unique features, structure, and arrangement of molecules that come together to create a cell. Some forms of breast cancer are seen more regularly among specific demographics.

This article investigates disparities in HR-positive/HER2-negative breast cancer — the most common type of breast cancer — among women of color.

Hormone receptor (HR) status and human epidermal growth factor 2 (HER2) status are two molecular identifiers that indicate how responsive breast cancer is to hormones and how quickly cancer cells will replicate.

Cells with positive HR status are significantly influenced by hormone production, which may make them more responsive to hormonal therapies. HR status depends on the presence or absence of two HR receptor sites, unique surface proteins, on breast cancer cells.

ER-positive means estrogen receptors are present. PR-positive indicates progesterone receptors are present. When one or both types of hormone receptors are on breast cancer cells, doctors classify the cancer as “HR-positive.”

The HER2 protein promotes faster growth in breast cancer cells. HER2 status is determined based on the amount of HER2 a cancer cell expresses on its surface. Cancer cells overexpressing HER2 are “HER2-positive,” while those that are “HER2 negative” have typical or absent HER2 levels.

Having HER2-negative breast cancer is associated with better outcomes because cancer typically grows slower.

According to survey data spanning 2016–2020, HR-positive/HER2-negative breast cancer is the most common female breast cancer subtype.

While white women have the highest overall risk for breast cancer in the United States, Black women and Hispanic women are the most likely to be diagnosed with more aggressive, advanced forms of breast cancer, such as triple-negative breast cancer (TNBC) and HER2-positive tumors.

Other racial and ethnic disparities seen in breast cancer include:

  • Black women are the most likely to die from breast cancer compared with any other racial or ethnic group.
  • Black women are more likely to receive a breast cancer diagnosis at a younger age.
  • Breast cancer is the leading cancer-related cause of death for Black and Hispanic women in the United States.
  • Black women, Hispanic women, and American Indian/Alaskan Native women are more likely to receive a diagnosis of progressed, or metastasized, breast cancer.

There are similar trends for women of color and HR-positive/HER2-negative breast cancer.

According to a 2021 review, HR-positive/HER2-negative breast cancer also has the highest prevalence among white women, followed by Black women, American Indian/Alaskan Native women, and Hispanic women.

In the research, Asian and Pacific Islander women consistently had the lowest rates across almost all breast cancer types, coming in slightly higher than white women for HR-negative/HER2-positive cancer.

Research from 2020 using more than 1,700 participants with HR-positive/HER2-negative breast cancer found statistically significant differences in baseline clinical characteristics between Black women and white women.

For the purposes of the study, researchers included Hispanic women and women of other races/ethnicities under the category of “white women.”

The findings showed:

  • Black women had a higher rate (31.2%) of high grade tumors compared with white women.
  • Black women were more likely than white women to have node positivity, the presence of cancer cells in the lymph nodes of the breast.
  • In Black women, tumors were more likely to be larger and at a more advanced stage.
  • Black women were more likely than white women to experience recurrence of HR-positive/HER2-negative breast cancer.

In general, HR-positive/ HER2-negative breast cancer is considered highly treatable. This is because it can respond to hormone therapies and is slower growing than many other subtypes.

The collective 5-year survival rate for HR-positive/HER2-negative breast cancer is 94.8%.

Within this overall rate, disparities still exist. According to a 2022 update from the American Cancer Society, the largest disparities are between Black women and white women.

In regards to mortality, the report noted Black women have the lowest 5-year relative survival rate out of any racial or ethnic group across all molecular breast cancer types and stages of disease.

Compared with white women at 96%, the 5-year relative survival rate for Black women with HR-positive/HER2-negative breast cancer was 88%.

Hispanic women and Asian and Pacific Islander women had the lowest mortality rates across all molecular subtypes of breast cancer.

Several factors can contribute to why a demographic experiences differences in health outcomes.

A 2023 review investigating disparities in breast cancer found several biological factors affecting outcomes in women of color, including:

  • more frequent rates of genetic alterations associated with hereditary breast cancer
  • increased levels of certain proteins that encourage cell growth, such as the Ki-67 protein
  • differences in ER and PR status in HR-positive breast cancer

Differences in breast cancer outcomes can also be affected by factors that limit access to quality or culturally relevant healthcare, such as:

  • poverty
  • lack of transportation
  • stigma
  • discrimination and racism
  • level of education

Learning more about HR-positive/HER2-negative breast cancer is the first step to feeling in control of the diagnosis and what it means for everyday life.

Developing an in-depth understanding of this breast cancer type can help a person regulate the potentially overwhelming emotions that come with a cancer diagnosis, such as fear, anger, or hopelessness.

Speaking with a cancer specialist and setting goals is also helpful. When expectations are clear and the path forward is well defined, the uncertainty in breast cancer diminishes.

As treatment begins, seeking guidance in counseling or joining a support group can help ward off feelings of isolation. Being with others who share a diagnosis creates a sense of camaraderie and mutual understanding.

HR-positive/HER2-negative is a molecular subtype of breast cancer that typically responds well to hormone therapy and is slower growing than many other breast cancers.

While white women are the most likely to receive a diagnosis of HR-positive/HER2-negative breast cancer and breast cancer overall, Black women and other women of color experience disparities in areas of mortality rates, stage of cancer, and recurrence rates, among others.