This study is for postmenopausal women aged 18 or older with stage I-III invasive breast cancer that is ER+/HER2- (estrogen receptor-positive/human epidermal growth factor receptor 2-negative). The researchers want to see how a marker called Ki67 changes after you receive endocrine therapy (hormone therapy) before your breast cancer surgery. They will compare these changes between women who carry the BRCA2 gene mutation and those who do not. To join, you must be scheduled for upfront surgery and be eligible for genetic testing if you are in the BRCA2 arm of the study. The study aims to assess the change in Ki67 expression from the start of endocrine therapy to at least two weeks into treatment.

Study design

This is an interventional study with a planned enrollment of 42 participants. It is not specified if it is randomized or blinded.

What's involved

You would have a core needle biopsy before starting endocrine therapy, which will include placing a biopsy marker clip. You will also have a blood draw.

Compensation

Not stated in the trial record.

Follow-up

The primary endpoint assesses changes in Ki67 from baseline to at least 2 weeks of endocrine therapy.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.