How is triple-negative breast cancer classified into six subtypes?

Triple-negative breast cancer (TNBC) predominantly occurs in premenopausal women and represents a highly aggressive subtype of breast cancer with a strong propensity for metastasis. It accounts for approximately 10–20% of all breast cancers and is defined by the absence (i.e., negativity) of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2).

What Are the Six Subtypes of Triple-Negative Breast Cancer?

Breast cancer is one of the most common malignancies among middle-aged women in recent years. Clinically, TNBC can be classified into six molecular subtypes: mesenchymal stem-like, mesenchymal, basal-like 1, basal-like 2, immunomodulatory, and luminal androgen receptor (LAR). Chemotherapy remains the mainstay of treatment for TNBC; moreover, subtype-specific chemotherapy regimens enable more precise therapeutic strategies. Clinically, TNBC follows an aggressive disease course associated with a high risk of distant metastasis—particularly to visceral organs (more frequent than bone metastasis) and the brain. The risk of distant recurrence peaks at approximately three years after diagnosis and may decline thereafter; however, overall prognosis remains poor, with a relatively high mortality rate.

Knowledge Expansion: Treatment Options for Triple-Negative Breast Cancer

1. Endocrine Therapy

Breast cancer is a hormone-dependent tumor whose growth is regulated by endogenous hormones. Estrogen and progesterone play critical roles in the development and progression of many breast cancers. Endocrine therapy aims to suppress tumor cell proliferation by either reducing systemic estrogen levels or blocking estrogen’s biological activity.

2. Receptor Inhibitors and Immunotherapy

Epidermal growth factor receptor (EGFR) is frequently overexpressed in TNBC, rendering it a potential therapeutic target. In addition to conventional treatments—including surgery, chemotherapy, and radiotherapy—immunotherapy has emerged as a novel antitumor strategy with promising efficacy against TNBC.

The above outlines the six molecular subtypes of triple-negative breast cancer. We hope this information is helpful to you.