IMMUNOHISTOCHEMISTRY, PROGESTERONE RECEPTOR (PR)

What this test checks

Measures progesterone receptor (PR) protein in breast cancer tissue. PR-positive breast cancers respond to hormone-blocking therapies alongside ER-positive status.

Why do people get this test?

PR status, alongside ER and HER2, forms the essential breast cancer receptor panel that determines the most effective treatment pathway. Combined receptor status predicts response to hormone therapy.

When you should consider this test

• After diagnosis of breast cancer — part of the standard ER/PR/HER2 receptor panel
• When planning hormone therapy for breast cancer
• When assessing prognosis of breast cancer

How to prepare

No preparation needed — performed on biopsy or surgical tissue.