Breast Biopsy - Oestrogen receptors (ER) and Progesterone receptors (PR)

Immunohistochemical staining of processed tissue with positive and negative controls.

• Oestrogen receptor (ER) and progesterone receptor (PR) staining is seen in the nucleus.
• A positive score is recorded where >10% of nuclei show at least weak expression for PR and ER on immunohistochemical staining.
• Alternatively a combined score of staining distribution and density (Quick score) may be used as follows:

Stainig distribution:

% of positive nuclei         Score

0                                    0

<1%                              1

1-10%                            2

11-33%                          3

34-66%                          4

67-100%                        5

Staining intensity:

Intensity                   Score

No staining                 0

Weak staining             1

Moderate staining        2

Strong staining            3

The distribution and intensity of scored are added to give a score out of 8.

• A score of zero indicates that endocrine treatments will be ineffective.
• A score of 2 or 3 indicates a small (20%) chance of response.
• A score of 4 to 6 indicates an even (50%) chance of response.
• A score of 7 or 8 indicates a good (75%) chance of response.
• Where progesterone receptor content has also been detirmined, endocrine treatment is considered appropriate for patients with low oestrogen receptor, but high progesterone receptor scores.