TheBreasties.org | Stage 4 Research

INVESTING IN STAGE 4 RESEARCH

The Breasties awarded its first $50,000 Stage 4 Research Grant to research led by Steffi Oesterreich, PhD, at Magee Women's Research Institute. The research investigates changes in the estrogen receptor that may contribute to treatment resistance and metastatic breast cancer, with the goal of advancing our understanding of why cancers stop responding to treatment and how those changes may be detected.
To date, The Breasties has awarded $140,000 to continue this work and is committed to expanding its investment in stage 4 research.

why it matters

People living with metastatic cancer need research that can change what is possible tomorrow and meaningful support for the realities they are navigating today.

The Breasties is building both.

Support for The Breasties stage 4 Initiatives help advance metastatic research while expanding access to education, community, representation, and connection for people living with stage 4 cancer.

What’s Being Studied

Researchers are focusing on estrogen receptor (ER) fusions in metastatic breast cancer (MBC). These fusions are rare but important genetic changes that can make breast cancer resistant to hormone therapy.

WHY THe COMMUNITY SELECTED THIS RESEARCH

For people living with Stage 4 ER+ breast cancer, one of the biggest challenges is that treatments that once controlled the cancer can eventually stop working. The Breasties is funding research aimed at understanding one reason that resistance develops—changes in the estrogen receptor—and building tools that could ultimately help detect resistance earlier and inform new treatment strategies.

WHY THIS MATTERS

Addresses a critical Stage 4 challenge: About 70% of breast cancers are ER+, and this research is focused on understanding why metastatic ER+ cancers can become resistant to hormone therapy.

Could improve future treatment: Identifying the ER changes that drive resistance could help lead to earlier detection of treatment resistance and more effective, personalized treatment strategies for people living with stage 4.

Building lab models that mimic ER fusions so scientists can study how they grow and spread.

Developing cutting-edge blood tests to detect ER fusions in patients, which could lead to earlier diagnosis of treatment resistance and better care.

145k+ Invested in Stage 4 research

Supporting research focused on metastatic breast cancer and treatment resistance.
Breakdown: $140K to Magee-Womens Research Institute + $5K to METAvivor.

July 2025 (Second Report – Making Strides)

Successfully created SSM3 cell models with ER fusions.

Found ER gene amplifications (extra gene copies), which may connect to treatment resistance.

ER fusions are now seen as a major driver of resistance to hormone therapy.

Advanced ER-fusion models and identified ER changes in patient blood.

Moved toward more precise blood-based testing to inform future treatments.

July 2024 (First Report – Getting Started)

Built the first ER-fusion cell models to study treatment resistance.

Began developing blood-based methods to detect ER fusions.

With Breasties support: researchers began building the first ER fusion cell models.

Early mouse studies showed that ER fusion tumors don’t easily spread, which raised new questions.

The Breasties Progress report August 2023

Generation and characterization of ER mutant models

Characterization of ER mutant metastases

Trish and Bri were the keynote speakers at the 34th Magee Survivorship Celebration.

Researchers advanced ER-mutant breast cancer models to study treatment resistance and metastasis.

2021 /2022

In 2021 The Breasties decide to expand their mission to include funding a $50k grant to fund stage 4 metastatic breast cancer.

We have started to characterize phenotypes of our ER mutant models such as breast cancer cell lines with some interesting ER fusion genes.

2019

In November of 2019, The Breasties Co-Founder Paige was invited to learn more about The Magee-Womens Research Institute.

When Paige arrived at Magee-Womens Research Institute, she was blown away by the incredible work they were doing and their research.

The Breasties is the first all-inclusive nonprofit organization that creates community for survivors, previvors, thrivers, and carevivors, impacted by breast and gynecologic cancers.

The Breasties is recognized as tax-exempt under Section 501(c)(3) of the Internal Revenue Code [tax-exempt status]. EIN: 82-4267245

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The Breasties is the first all-inclusive nonprofit organization that creates community for survivors, previvors, thrivers, and carevivors, impacted by breast and gynecologic cancers.

The Breasties is recognized as tax-exempt under Section 501(c)(3) of the Internal Revenue Code [tax-exempt status]. EIN: 82-4267245

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The Breasties stage 4 INITIATIVES

INVESTING IN STAGE 4 RESEARCH

why it matters

stage 4 research

145k+ Invested in Stage 4 research

Timeline of Progress