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Objectives |
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Method |
- The College of American Pathologists (CAP) provides two proficiency surveys for HER2 testing in breast cancer:
- Cases for IHC surveys are distributed twice annually.
- Two cases for FISH survey are distributed once annually.
- If possible, the same pathologic material is used for both the IHC and FISH survey. They are known as shared specimens.
- A series of six photomicrographs that were scored by a referee were also distributed.
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Authors’ Conclusions
“The level of concordance observed for the FISH surveys may reflect the nonambiguous and quantitative nature of FISH as compared with immunohistochemistry. …The immunohistochemistry survey results for the shared cases had much greater variability, particularly for the FISH-negative case… .”
“…a series of 6 photomicrographs were also assembled as a 1-page color print and distributed…. For even the case scored as 3+ by referees, 8 pathologists in participating laboratories interpreted the results as negative (a score of 0). This exercise also highlighted substantial disagreement for cases scored 1+ and 2+ by referees.”
| Research Leader Commentary |
The College of American Pathologists (CAP) interlaboratory testing program implemented by Cell Markers and Cytogenetics Committees sends laboratories unknown controls. The laboratory sends back the results, and CAP tells them whether they are doing a good or bad job. The more we can participate in voluntary programs to improve our performance, the better off we’ll be. This study found that using either IHC or FISH and the feedback from the CAP quality assurance program, laboratories can improve their test performance and standardization. Clearly, quality control and proficiency standards testing are very, very important. A laboratory needs to constantly re-evaluate whether they’re doing a good job.
Ann D Thor, MD
It has been consistently shown that FISH is superior to IHC. FISH is not a subjective test. If one can count dots, there should not be false positives. If false-positive FISH results were a real phenomenon, the College of American Pathologists’ (CAP) study should have detected it. CAP took cases it characterized and sent them to pathologists in community practice, not university pathologists. Ray Tubbs has done this study, and they are seeing great concordance.
Dennis Slamon, MD, PhD |
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