Breast cancers with a HER2/CEP17 ratio of 2.0 or greater and an average HER2 copy number of less than 4.0 per cell: frequency, immunohistochemical correlation, and clinicopathological features.
Hum Pathol
; 83: 7-13, 2019 01.
Article
em En
| MEDLINE
| ID: mdl-30121371
ABSTRACT
The 2013 American Society of Clinical Oncology and College of American Pathologists (ASCO/CAP) guidelines classified breast cancers with a fluorescence in situ hybridization dual-probe HER2/CEP17 ratio of 2 or greater as "amplified," inclusive of cases with a HER2 copy number less than 4. The 2018 ASCO/CAP update assigns HER2/neu status for the latter group in a fashion that is highly dependent on the associated immunohistochemical findings. Herein, the authors define the frequency, immunohistochemical correlates, and other clinicopathological features of breast cancers with HER2/CEP17 ratio of 2 or greater and HER2/neu copy number less than 4 (group A), based on an analysis of an institutional cohort assessed for HER2/neu status by both florescence in situ hybridization and immunohistochemistry and scored using 2013 ASCO/CAP criteria. Group A cases were compared with a group B of HER2/neu-amplified breast cancers with a HER2/neu copy number of 4 or greater regarding a variety of clinicopathological features. One hundred sixty-nine (14%) of 1201 cases were HER2/neu amplified, 18 (10.7%) in group A and 151 (89.3%) in group B. By immunohistochemistry, 61.1% of group A cases were HER2/neu negative, 7 (38.9%) were equivocal, and none were positive. In contrast, 66.9% of group B cases were HER2 positive (3+). We could not demonstrate statistically significant differences between the 2 groups regarding standard clinicopathological variables. In summary, our group A cases account for 1.5% of breast cancers, and 10.7% of all HER2/neu-amplified cancers classified as such based on 2013 ASCO/CAP criteria. They are predominantly HER2/neu negative by immunohistochemistry, which suggests that they are biologically different from classically HER2/neu-amplified cases and which validates the 2018 ASCO/CAP guideline against automatically classifying such cases as HER2/neu amplified.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Temas:
Geral
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Tipos_de_cancer
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Outros_tipos
Base de dados:
MEDLINE
Assunto principal:
Neoplasias da Mama
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Biomarcadores Tumorais
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Receptor ErbB-2
Tipo de estudo:
Guideline
Limite:
Adult
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Aged
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Aged80
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Revista:
Hum Pathol
Assunto da revista:
PATOLOGIA
Ano de publicação:
2019
Tipo de documento:
Article