ESTROGEN AND PROGESTERONE-RECEPTOR ASSESSMENT IN-CORE BIOPSY SPECIMENS OF BREAST-CARCINOMA

Aims-To assess the suitability of core biopsy specimens for the immuno histological assessment of oestrogen and progesterone receptors in bre ast carcinoma. Methods-Thirty consecutive cases of clinically palpable breast carcinoma, from which both core and excision biopsy specimens were available, were examined. Routinely processed paraffin wax sectio ns were stained using the specific monoclonal antibodies 1D5 (Dako) fo r oestrogen receptor and NCL-PGR (Novocastra) for progesterone recepto r, after an antigen retrieval step using a pressure cooker. Staining r esults were assessed using the H score system with the results being e xpressed as negative, weakly positive, moderately positive or strongly positive. Results-Twenty six biopsy specimens contained enough tumour tissue for assessment. Absolute agreement between scoring categories was seen in 19 (73%) cases for oestrogen receptors. However, when all positive categories were added together, agreement between core and ex cision biopsy specimens increased to 93% (24 cases). Disagreement was seen only in two cases which stained positive in the core biopsy speci mens and negative in the excision biopsy specimens. For progesterone r eceptors, the absolute agreement between all scoring categories was se en only in 11 (42%) cases. When all positive categories were considere d together, agreement increased to 69% (18 cases). Five cases were pro gesterone receptor positive in core but not in excisional biopsy speci mens, while three cases were negative in core but positive in excision al biopsy specimens. Conclusions-The results suggest that core biopsy specimens can be reliably used for oestrogen receptor assessment, but are less reliable for progesterone receptor assessment, probably becau se of a greater heterogeneity of progesterone receptor staining.