Reliability of immunohistochemical demonstration of oestrogen receptors in routine practice: interlaboratory variance in the sensitivity of detection and evaluation of scoring systems

摘要: Aims —To investigate interlaboratory variance in the immunohistochemical (IHC) detection of oestrogen receptors so as to determine rate false negatives, which could adversely influence decision give adjuvant tamoxifen treatment. Methods ensure that similar results are obtained by different institutions, 200 laboratories from 26 countries have joined UK national external quality assessment scheme for immunocytochemistry (NEQAS-ICC). Histological sections breast cancers having low, medium, and high levels receptor expression were sent each staining. The evaluated sensitivity detection, first estimating threshold values 1% 10% stained tumour cells, second Quick score method, a panel four assessors judging individual independently on single blind basis. also using participants' own values. Results —Over 80% able demonstrate positivity medium expressing tumours, but only 37% scored adequately low tumour. Approximately one third failed register any positive staining this tumour, while showed minimal positivity. Conclusions —There is considerable variability, especially relation with positivity, negative between 30% 60%. This variability appears be caused minor differences methodology may rectified fine adjustment overall technique.