IMMUNOHISTOCHEMISTRY, PROGESTERONE RECEPTOR (PR)

The IHC – Progesterone Receptor (PR) test is an immunohistochemistry-based diagnostic assay used to detect progesterone receptor expression in tissue samples. Progesterone receptors are proteins found within certain cells that respond to the hormone progesterone. In breast cancer pathology, PR status is an important biomarker used to evaluate tumor biology and guide treatment decisions.

This test is most commonly performed in patients with breast cancer to determine whether cancer cells express progesterone receptors. Tumors that are PR-positive are more likely to respond to hormone-based treatments, making PR testing a critical component of personalized cancer care.

The IHC PR test is routinely performed alongside Estrogen Receptor (ER) and HER2/neu testing as part of the standard breast cancer biomarker panel. Together, these markers help classify breast cancer, predict treatment response, and provide important prognostic information.

Benefits of the Test

• Helps classify breast cancer subtypes
• Assists in determining hormone receptor status
• Predicts response to hormone therapy
• Supports personalized treatment planning
• Provides valuable prognostic information

Why Doctors Recommend This Test

Doctors recommend the IHC PR test when evaluating breast cancer and hormone-sensitive tumors. It is commonly used in:

• Newly diagnosed breast cancer evaluation
• Breast tumor biopsy assessment
• Hormone receptor status determination
• Treatment planning and prognosis evaluation
• Recurrent breast cancer investigations
• Oncology pathology profiling

PR testing is frequently interpreted together with ER and HER2 results to determine the most appropriate treatment strategy for patients.

Preparation Before Test

No special preparation is required for this test. Important considerations include:

• The test is performed on a biopsy or surgical tissue sample
• No fasting is required
• No medication restrictions are generally necessary
• Clinical history and imaging findings may assist interpretation

Normal Reporting Time

The typical turnaround time is 3 to 5 working days, depending on tissue processing and laboratory workflow.

Who Should Take This Test

• Patients diagnosed with breast cancer
• Individuals undergoing breast biopsy evaluation
• Patients requiring hormone receptor analysis
• Cases needing treatment planning guidance
• Oncology patients requiring tumor biomarker profiling

The IHC PR test is an essential diagnostic tool in breast cancer management. By determining progesterone receptor status, it helps clinicians select the most effective therapies and develop individualized treatment plans.

Clinical Significance

PR immunostaining is commonly used in the evaluation of:

• Invasive breast carcinoma
• Ductal carcinoma of the breast
• Lobular carcinoma of the breast
• Recurrent breast cancer
• Hormone-sensitive tumors
• Selected gynecological malignancies

PR-positive tumors generally have a better response to endocrine therapy and may be associated with a more favorable prognosis compared with PR-negative tumors.