Why some estrogen-positive breast cancers keep growing without estrogen

Mechanism of estrogen independent proliferation in ER+ breast cancer cells

NIH-funded research Beckman Research Institute/city of Hope · NIH-11211302

This research looks for why some estrogen-receptor positive (ER+) breast cancers continue to grow despite hormone therapy and CDK4/6 drugs, aiming to help people with early-stage ER+ breast cancer.

Quick facts

Grant typeU01 cooperative agreement
Study typeNIH-funded research
Funding institutionBeckman Research Institute/city of Hope NIH-funded
Lab location1 site (Duarte, United States)
Project IDNIH-11211302 on NIH RePORTER

What this research studies

From a patient's perspective, researchers are trying to understand why some ER+ breast cancers stop responding to hormone therapy and CDK4/6 inhibitors. They study tumor samples taken before and during preoperative treatment and analyze individual cells' gene activity to see which signaling pathways become active in resistant tumors. In the lab they use matched cell models and a new mechanistic model linking estrogen and JNK signaling to cell-cycle control to test how increased CDK6 or loss of cell-cycle inhibitors lets cells restart growth. The team hopes to identify molecular signs of resistance that could guide better treatment decisions in the future.

Who could benefit from this research

Good fit: Ideal candidates are people with early-stage estrogen receptor–positive, HER2–negative breast cancer who are having preoperative or biopsy-linked treatment and sample collection.

Not a fit: People with estrogen receptor–negative or HER2‑positive breast cancer, or those not undergoing biopsy-based treatment, are unlikely to receive direct benefit from this research.

Why it matters

Potential benefit: If successful, this work could help doctors predict who will stop responding to hormone plus CDK4/6 therapy and suggest ways to prevent or overcome that resistance.

How similar studies have performed: Combining CDK4/6 inhibitors with hormone therapy has improved outcomes in metastatic ER+ breast cancer, but applying and fully understanding this approach in earlier-stage disease and the specific resistance mechanisms remains newer and less proven.

Where this research is happening

Duarte, United States

Researchers

About this research

  1. This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
  2. Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
  3. For full project details, budget, and progress reports, visit the official NIH RePORTER page below.
Conditions Breast CancerBreast Cancer CellBreast Cancer PatientCancer Control
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.