Breast cancer remains one of the most common cancers worldwide and continues to affect millions of women each year.

Researchers study ER+/HER2+ breast cancer samples to understand tumor biology better, identify biomarkers, and develop more targeted therapies for different breast cancer subtypes.

At Bay Biosciences, we provide high-quality ER+/HER2+ breast cancer samples and other oncology biospecimens to support cancer research, biomarker discovery, and precision oncology studies.

Our well-characterized biospecimens help researchers effectively investigate tumor progression, treatment response, molecular signaling pathways, and the tumor microenvironment.

Understanding ER+/HER2+ Breast Cancer

ER+/HER2+ breast cancer is a molecular subtype of breast cancer that expresses estrogen receptors (ER+) and elevated levels of human epidermal growth factor receptor 2 (HER2+).

Researchers consider ER+/HER2+ breast cancer biologically complex because both hormonal and HER2 signaling pathways influence tumor behavior.

Common symptoms of ER+/HER2+ breast cancer may include:

  • Breast lump or thickening
  • Changes in breast shape or size
  • Skin dimpling or irritation
  • Nipple discharge
  • Breast pain or swelling

Researchers continue to investigate how genetic, molecular, and immune-related factors contribute to tumor progression and therapeutic resistance in ER+/HER2+ breast cancer.

Bay Biosciences Breast Cancer Image

Breast Cancer Molecular Subtypes

Researchers classify breast cancer into several molecular subtypes based on hormone receptor status and HER2 expression.

These classifications help guide treatment decisions and improve patient stratification in oncology research.

Luminal A Breast Cancer

Luminal A is the most common subtype across all races and ages. Notably, these tumors tend to express estrogen receptor (ER+) and progesterone receptor (PR+) positive characteristics and typically grow slowly. Consequently, doctors typically administer hormonal therapy as treatment. 

Luminal B Breast Cancer

Luminal B tumors are frequently ER-positive and HER2-positive. These cancers tend to grow more aggressively than luminal A tumors. Luminal B breast cancers are likely to benefit from chemotherapy and may also benefit from hormone therapy and treatments that target the HER2 receptor.

HER2-Positive Breast Cancer

HER2-positive cancers are ER-negative and PR-negative and human epidermal growth factor receptor 2 (HER2+) positive.

Basal-Like Breast Cancer

This category typically includes triple-negative breast cancer, although not always. Triple-negative breast cancer occurs when the cells lack receptors for estrogen (ER-), progesterone (PR-), or HER2-. This type of breast cancer usually invades surrounding tissues and typically begins in the breast ducts.

Causes and Risk Factors of ER+/HER2+ Breast Cancer

ER+/HER2+ breast cancer arises from a combination of genetic, hormonal, and lifestyle factors.

Some of the most important contributors include:

Estrogen/Progesterone:

ER-positive breast cancer develops when estrogen binds to receptors within cancer cells and stimulates their growth. In some cases, both estrogen and progesterone attach to these receptors and promote tumor development.

Genetic mutations:

Inherited BRCA1/2 gene mutations and a family history of breast or ovarian cancer significantly increase risk.

Age:

Risk increases with advancing age, with the majority of breast cancer diagnoses occurring in women over 50.

Lifestyle factors:

Obesity, alcohol consumption, and physical inactivity are recognized modifiable risk factors linked to elevated breast cancer risk.

Diagnosis Of ER+/HER2+ Breast Cancer

Diagnosis of ER+/HER2+ breast cancer relies on a combination of imaging and molecular testing.

Typically, mammography and ultrasound are used to detect suspicious masses, after which a tissue biopsy is performed to confirm malignancy.

Moreover, the biopsy sample is tested to determine ER, PR, and HER2 receptor status, as well as Ki-67 levels to assess tumor proliferation rate.

Types of Breast Cancer Samples Used in Research

Researchers use multiple biospecimen types to study breast cancer biology, therapeutic response, and disease progression.

1. FFPE Breast Cancer Samples

FFPE breast cancer samples are among the most widely used oncology biospecimens in translational research.

2. Breast Tumor Samples

Breast tumor samples provide direct access to malignant tissue and surrounding stromal components. Researchers analyze these biospecimens to study tumor growth, angiogenesis, immune infiltration, metastatic behavior, and therapeutic resistance.

3. Breast Cancer Plasma Samples

Breast cancer plasma samples support liquid biopsy research. Researchers analyze circulating tumor DNA (ctDNA), proteins, cytokines, metabolites, and extracellular vesicles to identify disease-associated molecular signatures.

4. Triple Positive Breast Cancer Samples

Triple positive breast cancer samples express estrogen receptors (ER+), progesterone receptors (PR+), and HER2 positivity. Researchers use these biospecimens to investigate the interaction between hormone receptor pathways and HER2 signaling.

5. Human Breast Cancer Tissue

Human breast cancer tissue samples provide important insight into tumor histology, cellular organization, and molecular abnormalities associated with breast cancer progression. Moreover, human tissue samples are considered to be valuable for both basic and translational oncology research.

Applications of Breast Cancer Samples in Research

Researchers use breast cancer samples across multiple areas of oncology and precision medicine research.

Breast Cancer Biomarker Discovery

Scientists analyze breast cancer biospecimens to identify biomarkers associated with early detection, tumor progression, metastasis, and therapeutic response.

Moreover, they study proteins, nucleic acids, cytokines, metabolites, and circulating tumor markers. This helps improve diagnostic and prognostic tools. 

Drug Development and Therapeutic Research

Pharmaceutical researchers use ER+/HER2+ breast cancer samples to evaluate experimental therapies targeting hormone receptor pathways, HER2 signaling, immune checkpoints, and tumor metabolism.

These biospecimens help researchers better understand therapeutic response, drug resistance mechanisms, and treatment-associated molecular changes.

Tumor Microenvironment Research

Researchers increasingly study the breast tumor microenvironment to understand how immune cells and stromal interactions influence tumor behavior. These studies are important because they contribute to the development of more effective immunotherapies and combination treatment strategies.

Supporting Your Research with Bay Biosciences

At Bay Biosciences, we provide high-quality breast cancer samples for translational and pharmaceutical research applications.

We follow strict collection, processing, storage, and quality control procedures to maintain biospecimen integrity and ensure reliability in research findings.

Our comprehensive range of ethically-sourced biospecimens includes:

If you need customized biospecimens or additional information about available samples, please feel free to contact us. We are always happy to help!