IHC

Progesterone Receptor (PR)

Identifies a nuclear hormone receptor regulated by estrogen receptor (ER) activity and used as a marker of an intact ER pathway. Progesterone receptor (PR) is expressed in 60–70% of invasive breast cancers and provides additional predictive value alongside ER for determining response to endocrine therapies, including tamoxifen, SERMs, and aromatase inhibitors. Its primary clinical use is to help predict benefit from hormonal treatment in both early-stage and metastatic breast cancer.

Synonyms

PgR

Full Description

Identifies a nuclear hormone receptor regulated by estrogen receptor (ER) activity and used as a marker of an intact ER pathway. Progesterone receptor (PR) is expressed in 60–70% of invasive breast cancers and provides additional predictive value alongside ER for determining response to endocrine therapies, including tamoxifen, SERMs, and aromatase inhibitors. Its primary clinical use is to help predict benefit from hormonal treatment in both early-stage and metastatic breast cancer.

Methodology

IHC

Specimen Requirements

Tissue Block: Formalin-fixed, paraffin-embedded (FFPE) tumor block preferred. Unstained Slides: Recommended 2 charged slides per stain requested (minimum of 1 slide per stain), baked or unbaked. Fixation: Tissue must be fixed in 10% neutral buffered formalin for 6–72 hours.

Storage and Transportation

Use cold pack for transport. Make sure cold pack is not in direct contact with specimen.

Turnaround Time

Global: 48 Hrs, Image Analysis (tech-only): 36 Hrs, Tech-Only (stain only): 24 Hrs

CPT Codes

88342x1 or 88341x1 (qualitative IHC) or 88360 (quantitative/semi-quantitative – manual) or 88361x1 (quantitative/semi-quantitative – computer assisted)