Breast biopsy ER and PR receptors

Formalin-fixed paraffin embedded breast tissue. For optimum results tissues should be sliced to facilitate fixation.

Immunohistochemical staining of processed tissue with positive and negative controls.

To determine if tumours are potentially responsive to anti-oestrogen treatment.

• Oestrogen receptor (ER) and progesterone receptor (PR) staining are 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:

Staining 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 determined, endocrine treatment is considered appropriate for patients with low oestrogen receptor, but high progesterone receptor scores.