# Estradiol in ER-beta-positive TNBC

Source: https://onco.cc/trials/nct03941730/  
OnCo record `nct03941730` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

This study tests estradiol in triple-negative breast cancers that express a different estrogen receptor, ER beta. That selection differs from the usual ER-alpha test used to classify breast cancer.

## Summary

This study tests estradiol in triple-negative breast cancers that express a different estrogen receptor, ER beta. That selection differs from the usual ER-alpha test used to classify breast cancer.

Interventional study registered as NCT03941730, sponsored by Mayo Clinic. Registry phase: 2. Registry enrollment is 8 participants (actual). Registry status checked October 10, 2026: active not recruiting. UCSF lists this study as closed to local enrollment; local availability and overall registry status are separate. See the registry for full eligibility and current sites.

## Fields

- Kind: Trial
- Status: active
- Last checked: 2026-10-10
- Also known as: Estradiol in Treating Patients With ER Beta Positive, Triple Negative Locally Advanced or Metastatic Breast Cancer
- Tags: ucsf-breast-coverage; interventional
- Registry id: NCT03941730
- Phase: 2
- Setting: ER-beta-positive locally advanced or metastatic triple-negative breast cancer
- Sponsor: Mayo Clinic
- Enrolled: 8

## Sources

- ClinicalTrials.gov NCT03941730: https://clinicaltrials.gov/study/NCT03941730
- UCSF study listing and local availability: https://clinicaltrials.ucsf.edu/trial/NCT03941730

## Connected records

- cancers: [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/), [Triple-negative breast cancer (TNBC)](https://onco.cc/cancers/tnbc/)
- institutions: [UCSF Helen Diller Family Comprehensive Cancer Center](https://onco.cc/institutions/ucsf/)

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