Interview IHC Standardization - Dako

Interview IHC Standardization
Thomas Boenisch
Dako North America
Consultant and Researcher in Immunology
The fact that we have been providing our customers
“
with the staining reagents in “kit format” since 1979/80
was an important step towards standardization as it
has provided consistent reagents. ”
Connection: What constitutes standardization in an anatomic
pathology lab?
T. Boenisch: Although I have used the word “standardization” in some
of my own publications for Immunohistochemistry (IHC), I would like
to define this as “consistency and/or reproducibility”. Coming from
clinical chemistry, the term “standardization” would imply the use
of quantitative calibrators or standards, which of course is not
possible in IHC.
In an anatomic pathology lab, all procedures – beginning from surgery
to staining the tissue sections should be subject to “standardization”.
This should also include the use and the preparation of glass slides
as they are routinely treated with different adhesives. Wrong or
inconsistent type of slides can cause wrinkles and/or other distortions
depending on the tissues, and can result in uneven staining patterns.
Connection: How well is the “prefixation” process standardized?
Is it possible to standardize this process?
T. Boenisch: “Prefixation” includes the preparation of the tissue
specimen. The size of the biopsy needs to be standardized (ideally
to 1 cm 3 ). It is important to keep in mind that denser tissues are more
slowly penetrated by formalin, and hence require longer incubation
in formalin.
Connection: What does Dako provide in terms
of standardization?
T. Boenisch: The fact that we have been providing our customers with
the staining reagents in “kit format” since 1979/80 was an important
step towards standardization as it has provided consistent reagents.
Connection: Why is standardization in diagnostic pathology
important?
T. Boenisch: The consistency and reliability of the staining results is
what enables the pathologist to make correct interpretations in both,
diagnosis and prognosis.
Connection: How would you like to standardize?
T. Boenisch: Ideally, the vendor should provide unstained and
stained sections of tissues to serve as “guides”. This allows the
laboratory and the pathologist to make valid comparisons with the
patient’s processed sections. Although this approach may be a
challenge for most vendors, the pathology laboratory will be provided
with valuable guidance. This, however, would require that the vendor
must be informed about the origin of the sections and optimal
fixation. Unknown samples must be routinely subjected to antigen
retrieval (AR)
The negative consequences of differences in the length of
fixation, especially over-fixation can be eliminated (with few
exceptions) by the universal and routine use of AR. This concept
has been published: Shi et. al., Applied Immunohistochemistry
& Molecular Morphology 1998: 6: 89-96, and Boenisch, Applied
Immunohistochemistry & Molecular Morphology 2005: 13: 283-286.
Connection: In your opinion, what is the biggest hurdle
for standardization?
T. Boenisch: Two of the biggest hurdles are: 1) disregarding optimal
fixations, and 2) inconsistent use of AR.
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Connection: Which product of Dako best personifies the
standardization process and why?
T. Boenisch: Kits and AR reagents best personify standardization as
they provide reagents and tissues of nearly uniform and comparable
quality regardless of the inconsistencies created by uncontrolled
fixation.
Connection: Would procedural simplification aid standardization?
T. Boenisch: Yes. I have shown in my recent publication (Boenisch, T.
Pre-treatment for Immunohistochemical Staining Simplified. Applied
Immunohistochemistry & Molecular Morphology. 15(2):208-212, June
2007) that this is possible. Here I compared several procedures for the
pre-treatment of formalin-fixed and paraffin-embedded tissue sections
and showed that a simpler approach than what is routinely used today
is possible.
Connection: Can we have a standardized procedure to interpret
IHC assays
T. Boenisch: Yes. For instance, when interpretations are based on
the number of stained cells or nuclei, but less so when the intensity of
staining is relied on.
Connection: How has Dako contributed to IHC standardization?
How is it involved in the development of IHC products?
T. Boenisch: Dako was the first vendor to commercialize the “kit
format” for IHC in 1979/80. During the following 28 years Dako has
supported consistency of staining through this step.
Connection: How do you assure that Dako’s reagents work
on a variety of patient samples-for instance, patients from
different countries?
T. Boenisch: Use of our IHC kits has consistently given reproducible
results in all parts of the world since we started making them. Also, we
have always consistently subscribed to the principles and approaches
outlined by the Ad-Hoc Committee on Immunohistochemistry
Standardization. Goldstein, Neal S. MD; Hewitt, Stephen M. MD,
PhD; Taylor, Clive R. MD, DPhil; Yaziji, Hadi MD; Hicks, David G.
MD; Members of Ad-Hoc Committee On Immunohistochemistry
Standardization. Applied Immunohistochemistry & Molecular
Morphology. 15(2):124-133, June 2007. With due modesty, I would
like to point out that my work in this field has been quoted repeatedly.
Connection: What is validation and how does it fit
into standardization?
T. Boenisch: “Standardization” of IHC requires the correct application/
use of recommended procedures, including the simultaneous
staining of provided controls. And, I would like to emphasize, by
the documented benefits of the routine use of AR procedures for
all antigens (Boenisch, Applied Immunohistochemistry & Molecular
Morphology 2005: 13: 283-286).
Connection: You were one of four who started Dako in
Santa Barbara, CA in 1979. You retired in 1993, but you keep
publishing in peer-reviewed journals – including your recent
Applied Immunohistochemistry & Molecular Morphology
paper in June of 2007. How have you kept up with the changes
in the industry, and what do you do in your spare time.
T. Boenisch: My continuing interest in IHC is largely based on
my general interest in protein chemistry. I have kept abreast of the
many changes by reading new publications, being a member of the
“Committee for the Standardization of IHC” and by many “hands-on”
experiments in Dako’s R&D department.
In my spare time, I engage in oil painting and participate in the Santa
Barbara Art Show on Sundays; listening to the classical music and
opera (remember, I am from Vienna, Austria), and then of course
growing orchids and succulents.
Contact Information:
Name Thomas Boenisch
Title Consultant and Researcher in Immunology
Company Dako North America
Address 6392 Via Real | Carpinteria | CA 93013
Country Austria/ USA
Email tomboenisch@cox.net
Education Diploma in Engineering. Vienna, Austria.
Experience & Responsibilities
Director of Immunochemistry and VP. Dako Corporation,
Santa Barbara, CA, USA 1979-93
Member of the Subcommittee: Quality Assurance for
Immunohistochemistry. Clinical and Laboratory Standards Institute,
Wayne, PA, USA 2005-2007.
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