Table 1 Recommendations for staining and assessment of ER and PgR
Critical factors
StainingOptimal fixation
Antigen retrieval—citrate pH 6.0, but test higher pH buffers if suboptimal staining
Antibody validated against biochemical assay
Positive control with range of staining; choose test tissue with normal breast included if possible
Quality assurance, internal and external
AssessmentNuclear staining only; cytoplasmic staining may be due to excess antigen retrieval
Only invasive cancer assessed
Strong relationship with grade, so if grade I low/negative repeat
Use a recognised scoring system. Allred score easy to use and identifies low positive cases