Table 1

Details of tumours circulated by UK NEQAS-CC for assessments between April 1994 and June 1998

Degree of expression
Run no.DateNumber of labsTumour type(s)ReceptorIHCCytosol
All tumours were fixed for 24 hours in 10% neutral buffered formalin.
ER/PR expression of tumours by IHC is described in terms of the proportion of invasive nuclei staining (%) and the average staining intensity (+, ++, +++).
Cytosol values of expression are in fmol/mg protein.
*Composite blocks containing more than one tumour were used for these assesments.
†Participants not stocking an antibody to PR were asked to demonstrate ER instead. On these runs tumours were chosen that have very similar expression of ER and PR, as determined by IHC at the organising laboratory.
‡On this assessment, participants were asked to demonstrate both ER and PR.
ER, oestrogen receptor; IDC, infiltrating ductal carcinoma; IHC, immunohistochemistry; Inf., infiltrating; mets, metastatic; PR, progesterone receptor.
264/9437IDCER100%, +++Not performed
292/9566IDC (mets)ER100%, +++Not performed
32*12/9598Inf./DCISER100%, +++Not performed
ILC80–90% ++Not performed
34*8/96105IDCER90–100%, +++ER = 248
ILC75–80% , ++ER = 29
IDC0%ER = 0
361/97118IDCPR/ER†90%, +++ER = 66, PR = 307
38*4/97175IDCER90–100%, +++ER = 122
IDC90%, ++ER = 41
IDC0%ER = 7
39*8/97176IDCPR/ER†99–100%, +++ER = 309, PR = 1582
ILC75%, ++ER = 11, PR = 21
IDC1%, +ER = 7, PR = 6
40*12/97192IDCER99%, +++ER=15
IDC99%, +++ER=11
IDC90%, ++ER = 12
414/98178IDCER and PR‡ER = 75–80%, ++ER = 10
PR = 0%PR = 2
42*6/98205IDCER100%, +++ER = 70
IDC90%, ++ER = 41
IDC15%, +ER = 65