Breast biopsy ER and PR receptors

Keywords: Breast biopsy - oestrogen receptors (ER) and progesterone receptors (PR)

Specimen:

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

Method:

Immunohistochemical staining of processed tissue with positive and negative controls.

Application:

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

Interpretation:
  • 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.
Reference:

Leake R et al. J Clin Pathol 2000; 53: 634-635.