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Figure 4. External Controls
A B
C
Figure legend: Optimal external (ideally on-slide) controls for both ER and PgR should
include multiple tissues including ones with expected strong staining, lower limit of
detection levels and negative controls; tonsil and cervix have been used to meet these
criteria. Panel A (200x) shows tonsil tissue with optimal staining for ER to ensure an
appropriate low limit of detection; dispersed germinal center cells and the squamous
epithelium should be ER positive but the B-cells in the mantle zones should be ER
negative. In contrast to ER, no nuclear PgR staining should be seen in tonsillar tissue.
Weak positive PgR staining in tonsil should result in work-up to determine if assay dri
has occurred. Panel B (200×) shows PgR variably staining the basal layer of the squamous
mucosa as expected (this staining should ensure an appropriate low limit of detection for
PgR). Stromal cells stain strongly for both ER and PgR. ER should stain the squamous
mucosa more uniformly (not just the basal layer) with at least moderate to strong stain
intensity. Panel C (200×) shows PgR staining should also be positive in the endocervical
columnar epithelial cells (with some variability expected). ER should stain almost all
endocervical columnar epithelial cells. Of note, it should be taken into consideration
that hormone receptor staining of cervical tissue may be reduced in tissue from post-
menopausal women.
