Abstract
Semiquantitative immunohistochemistry (IHC) is commonly used in combination with fluorescence in situ hybridization (FISH) to detect HER2 amplification in gastroesophageal adenocarcinomas. Most laboratories apply these tests in a sequential algorithm, using IHC as a frontline test and reserving FISH for IHC-equivocal cases. To gain a better understanding of the concordance of IHC and FISH results at our institution, we identified all gastroesophageal adenocarcinomas at our institution tested for HER2 (n=125). Matched IHC and FISH were available for 116 cases (94%). Cases consisted of adenocarcinoma of the distal esophagus (22%), gastroesophageal junction (24%), stomach (43%), and metastatic sites (12%). A total of 88 cases (70%) were biopsies, whereas 37 cases (30%) were resections. Overall, 15 cases (13%) were HER2 positive (IHC 3+ and/or FISH amplified). A total of 60 cases (52%) were IHC score 0; none of these were HER2 amplified by FISH. A total of 30 cases (26%) were IHC 1+; 5 (17%) of these cases were HER2 amplified by FISH. A total of 20 cases (17%) were IHC 2+; 4 (20%) of these cases were HER2 amplified by FISH. A total of 6 cases were IHC score 3+; all of these were HER2 amplified by FISH. Although there was a high overall concordance between IHC and FISH results (96%), a subset (17%) of IHC-negative cases (score 1+) were HER2 amplified as evaluated by FISH, representing 33% of all HER2 amplified cases. This suggests that the common practice of limited FISH testing to IHC 2+ cases will miss a significant number of HER2 amplified cases.
| Original language | English (US) |
|---|---|
| Journal | Applied Immunohistochemistry and Molecular Morphology |
| DOIs | |
| State | Accepted/In press - May 5 2016 |
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ASJC Scopus subject areas
- Pathology and Forensic Medicine
- Medical Laboratory Technology
- Histology
Cite this
HER2 Status in Gastroesophageal Adenocarcinomas : Correlation Between Immunohistochemistry and Fluorescence In Situ Hybridization Methodologies. / Robertson, Scott A.; Cimino-Mathews, Ashley M; Cornish, Toby C.
In: Applied Immunohistochemistry and Molecular Morphology, 05.05.2016.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - HER2 Status in Gastroesophageal Adenocarcinomas
T2 - Correlation Between Immunohistochemistry and Fluorescence In Situ Hybridization Methodologies
AU - Robertson, Scott A.
AU - Cimino-Mathews, Ashley M
AU - Cornish, Toby C.
PY - 2016/5/5
Y1 - 2016/5/5
N2 - Semiquantitative immunohistochemistry (IHC) is commonly used in combination with fluorescence in situ hybridization (FISH) to detect HER2 amplification in gastroesophageal adenocarcinomas. Most laboratories apply these tests in a sequential algorithm, using IHC as a frontline test and reserving FISH for IHC-equivocal cases. To gain a better understanding of the concordance of IHC and FISH results at our institution, we identified all gastroesophageal adenocarcinomas at our institution tested for HER2 (n=125). Matched IHC and FISH were available for 116 cases (94%). Cases consisted of adenocarcinoma of the distal esophagus (22%), gastroesophageal junction (24%), stomach (43%), and metastatic sites (12%). A total of 88 cases (70%) were biopsies, whereas 37 cases (30%) were resections. Overall, 15 cases (13%) were HER2 positive (IHC 3+ and/or FISH amplified). A total of 60 cases (52%) were IHC score 0; none of these were HER2 amplified by FISH. A total of 30 cases (26%) were IHC 1+; 5 (17%) of these cases were HER2 amplified by FISH. A total of 20 cases (17%) were IHC 2+; 4 (20%) of these cases were HER2 amplified by FISH. A total of 6 cases were IHC score 3+; all of these were HER2 amplified by FISH. Although there was a high overall concordance between IHC and FISH results (96%), a subset (17%) of IHC-negative cases (score 1+) were HER2 amplified as evaluated by FISH, representing 33% of all HER2 amplified cases. This suggests that the common practice of limited FISH testing to IHC 2+ cases will miss a significant number of HER2 amplified cases.
AB - Semiquantitative immunohistochemistry (IHC) is commonly used in combination with fluorescence in situ hybridization (FISH) to detect HER2 amplification in gastroesophageal adenocarcinomas. Most laboratories apply these tests in a sequential algorithm, using IHC as a frontline test and reserving FISH for IHC-equivocal cases. To gain a better understanding of the concordance of IHC and FISH results at our institution, we identified all gastroesophageal adenocarcinomas at our institution tested for HER2 (n=125). Matched IHC and FISH were available for 116 cases (94%). Cases consisted of adenocarcinoma of the distal esophagus (22%), gastroesophageal junction (24%), stomach (43%), and metastatic sites (12%). A total of 88 cases (70%) were biopsies, whereas 37 cases (30%) were resections. Overall, 15 cases (13%) were HER2 positive (IHC 3+ and/or FISH amplified). A total of 60 cases (52%) were IHC score 0; none of these were HER2 amplified by FISH. A total of 30 cases (26%) were IHC 1+; 5 (17%) of these cases were HER2 amplified by FISH. A total of 20 cases (17%) were IHC 2+; 4 (20%) of these cases were HER2 amplified by FISH. A total of 6 cases were IHC score 3+; all of these were HER2 amplified by FISH. Although there was a high overall concordance between IHC and FISH results (96%), a subset (17%) of IHC-negative cases (score 1+) were HER2 amplified as evaluated by FISH, representing 33% of all HER2 amplified cases. This suggests that the common practice of limited FISH testing to IHC 2+ cases will miss a significant number of HER2 amplified cases.
UR - http://www.scopus.com/inward/record.url?scp=84965069983&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84965069983&partnerID=8YFLogxK
U2 - 10.1097/PAI.0000000000000382
DO - 10.1097/PAI.0000000000000382
M3 - Article
C2 - 27153447
AN - SCOPUS:84965069983
JO - Applied Immunohistochemistry and Molecular Morphology
JF - Applied Immunohistochemistry and Molecular Morphology
SN - 1541-2016
ER -