8
Diagnosis
Figure 1. Recommendations for Scoring (Readout) and
Interpretation of IHC Test to Determine ER Status
in Breast Cancers
Step 1: Checklist for initial quality control
a
:
❑ The sample is adequate for biomarker testing:
Receptor testing should not be interpreted on any specimen
that has insufficient invasive cancer for interpretation or severe
processing artifacts
❑ External and internal controls (if present) stain appropriately
If controls are not working as expected, the test should not be
reported until the issue has been addressed.
❑ Pre-analytical variables (fixative type, time to fixation, time in fixation)
are documented
If this information is not available to the laboratory, a comment
should be added to the report that the results should be interpreted
with caution.
Steps to consider including in SOP:
• Re-review of controls
• A second reviewer to confirm interpretation
• Validated quantitative digital image analysis to confirm
interpretation
• Comparison of result with any prior patient-specific results
• Retesting the same sample if analytic issues suspected
(ex. controls did not work as expected)
• Repeating the test on a different block or subsequent
specimen if there are no internal controls, pre-analytic issues
are suspected or result is unusual or unexpected
a
Hormone receptor testing should be done only with a validated method and with appropriate
laboratory procedures including ongoing assay monitoring and pathologist competency assessment.
b
For ER Low Positive results include comment: "e cancer in this sample has a low level (1-10%)
of ER expression by IHC. ere are limited data on the overall benefit of endocrine therapies for
patients with these results, but they currently suggest possible benefit, so patients are considered
eligible for endocrine treatment. ere are data that suggest invasive cancers with these results are
heterogeneous in both behavior and biolog y and oen have gene expression profiles more similar to
ER negative cancers."
c
If no internal controls are present but external controls are positive include comment: "No internal
controls are present, but external controls are appropriately positive. If needed, testing another
specimen that contains internal controls may be warranted for confirmation of ER status."
For PgR testing : e same overall interpretation principles apply to PgR but the above reporting
elements are recommended only for ER testing. PgR should be interpreted as either Positive (if
1-100% of cells have nuclear staining ) or Negative (if <1% or 0% of cells have nuclear staining ) with
the overall percentage and intensity of staining reported.
