3
Recommendation 1.1. Optimal algorithm for ER/PgR testing
➤ Samples with 1-100% of tumor nuclei positive for ER or PgR are
interpreted as positive. For reporting of ER (not PgR), if 1-10% of
tumor cell nuclei are immunoreactive the sample should be reported
as ER Low Positive with a recommended comment (see Figure 1 and
Table 2). A sample is considered negative for ER or PgR if <1% or 0%
of tumor cell nuclei are immunoreactive. A sample may be deemed
uninterpretable for ER or PgR if the sample is inadequate (insufficient
cancer or severe artifacts present, as determined at the discretion
of the pathologist), external and internal controls (if present) do not
stain appropriately or if pre-analytical variables have interfered with
the assay's accuracy (see Figures 1-4). Clinicians should be aware
of and able to discuss with patients the limited data on ER Low
Positive cases and issues with test results that are close to a positive
threshold. (Strong Recommendation; EB-H)
Recommendation 1.2. Optimal testing conditions (no change)
➤ Large, (preferably multiple) core biopsies of tumor are preferred for
testing if they are representative of the tumor (grade and type) at
resection. Accession slip and report must include guideline-detailed
elements. (Strong Recommendation; EB-H)
Recommendation 1.3. Optimal tissue handling requirements
(no change)
➤ Time from tissue acquisition to fixation should be as short as
possible. Samples for ER and PgR testing are fixed in 10% neutral
buffered formalin (NBF) for 6 to 72 hours. Samples should be sliced
at 5-mm intervals after appropriate gross inspection and margins
designation and placed in sufficient volume of NBF to allow adequate
tissue penetration. If tumor comes from remote location, it should
be bisected through the tumor on removal and sent to the laboratory
immersed in a sufficient volume of NBF. Cold ischemia time, fixative
type, and time the sample was placed in NBF must be recorded. As in
the ASCO/CAP HER2 guideline, using unstained slides cut more than
6 weeks before analysis is not recommended. Time tissue is removed
from patient, time tissue is placed in fixative, duration of fixation,
and fixative type must be recorded and noted on accession slip or in
report. (Strong Recommendation; EB-H)
Diagnosis
