March 2008
Feature Story

Enrollment in the College's HER2 Surveys has climbed over the past two years, making the need for pathologists to donate breast cancer tumor tissue to support the Surveys greater than ever, says Raymond Tubbs, DO, a member of the CAP Surveys Committee and section head of molecular genetic pathology at the Cleveland Clinic.

Many assume the CAP has ample material when "in fact the need is great and pressing," Dr. Tubbs says. "Some College members have been very helpful in providing tissue specimens, but we need to broaden that base of support."

Without an increase in tissue specimen donations, the College may come close this year to facing a serious shortage. If that were to occur, Dr. Tubbs says, "we would have to limit the number of participants or subscribers in the Surveys." And that limitation would affect the ability of laboratories to do HER2 testing because every CAP-accredited lab that performs HER2 testing must participate in a proficiency testing program.

The CAP depends on having anonymized, redundant breast cancer tissue to create several Surveys. These are the HER2 tissue microarray (TMA) Survey (IHC for HER2), the CYH Survey (FISH for HER2), PM-2 (ER IHC Survey), and the new ISH2 (HER2 brightfield ISH Survey-CISH or SISH).

It's not only that many more labs are participating in HER2 proficiency testing, but also that the number of cases used in the Surveys has increased considerably. In the past, HER2 PT requirements were met using a single whole section in the MK (immunohistochemistry) Survey, Dr. Tubbs says. But now a lab participating in the IHC HER2 TMA Survey must test tissue microarray cores from 80 separate breast cancer cases each year (40 case cores twice each year). The CYH and ISH2 Surveys require laboratories to test 20 separate case cores annually.

• Paraffin blocks from invasive breast carcinomas of any type.
• Coexistent DCIS is acceptable if it is a relatively minor component.
• Invasive carcinoma should be at least 1 cm 1 cm on the glass slide.
• Tissue must be fixed in 10 percent neutral buffered formalin from six to 48 hours. Ideally, says Dr. Tubbs, the tissue would have been fixed overnight.
• Block thickness of 2 mm minimum, 3-4 mm ideal.
• Five paraffin blocks per case. The "requirement for the five paraffin blocks is based on very practical experience preparing tissue microarrays for the Surveys program over several years," Dr. Tubbs says. "Of course, if more than five blocks are available, the additional tissue blocks can certainly be used." The laboratory should keep one paraffin block from the case for future possible diagnostic/prognostic clinical testing needs.
• The donated material should be free of all patient identifiers.

Metastatic tumor from the breast, liver, lymph nodes, and other sites is also acceptable, provided the preceding fixation and size requirements are met and the tissue hasn't been exposed to a decalcification solution.

Pathologists should not be discouraged from sending cases that are several years old. "If they have five blocks they can release to us, we will pretest the blocks and will know if the blocks are suitable for use" in a Survey, Dr. Tubbs says. Not every tissue specimen submitted for inclusion in the Surveys can be used. "Sometimes the tissue is necrotic, or there may be an issue of genomic heterogeneity or lack of representative invasive carcinoma," Dr. Tubbs explains. Gene Herbek, MD, of Methodist Hospital in Omaha, Neb., whose hospital donates tumor tissue to the Surveys program, says the key to donating usable specimens is to get "viable tumor in every block-1 cm per block-and not fatty tissue or necrotic tissue."

The lab donating breast cancer tissue must obtain approval to do so from the hospital Institutional Review Board. "This is essential to do," Dr. Tubbs says. "In many hospitals, the IRB will grant a waiver or exemption of informed consent requirements based on the use of anonymous samples."

One obstacle to donating the tissue is the extra work required, Dr. Tubbs concedes. For example, seeking IRB approval does take time, and "having technologists to do the work is somewhat challenging in that a lot of labs are under pressure related to staffing. But as a profession, we have to think about this as an investment in the quality of work we do," he says. Dr. Herbek reports that the College helped him complete the required forms for Methodist Hospital's IRB, which quickly approved the use of excess breast cancer tissue for the Surveys. Now the hospital's breast center donates "dozens and dozens [of paraffin blocks] on a fairly regular basis."

"Submitting the tissue hasn't been difficult," Dr. Herbek says. "The hospital has been very supportive of this effort to promote laboratory and patient care quality. It wasn't a hard sell at all."