Retrospective observational study of HER2 immunohistochemistry in borderline breast cancer patients undergoing neoadjuvant therapy, with an emphasis on Group 2 (HER2/CEP17 ratio ≥2.0, HER2 copy number <4.0 signals/cell) cases.
Br J Cancer
; 124(11): 1836-1842, 2021 05.
Article
en En
| MEDLINE
| ID: mdl-33762723
ABSTRACT
BACKGROUND:
The ASCO/CAP guidance on HER2 testing in breast cancer (BC) has recently changed. Group 2 tumours with immunohistochemistry score 2+ and HER2/CEP17 ratio ≥2.0 and HER2 copy number <4.0 signals/cell were re-classified as HER2 negative. This study aims to examine the response of Group 2 tumours to neoadjuvant chemotherapy (NACT).METHODS:
749 BC cases were identified from 11 institutions. The association between HER2 groups and pathological complete response (pCR) was assessed.RESULTS:
54% of immunohistochemistry HER2 positive (score 3+) BCs showed pCR, compared to 19% of immunohistochemistry 2+ FISH amplified cases. 27% of Group 2 treated with HER2 targeted therapy achieved pCR, compared to 19 and 11% in the combined Groups 1 + 3 and Groups 4 + 5, respectively. No difference in pCR rates was identified between Group 2 and Group 1 or combined Groups 1 + 3. However, Group 2 response rate was higher than Groups 4 + 5 (p = 0.017).CONCLUSION:
No difference in pCR was detected in tumours with a HER2/CEP17 ratio ≥2.0 and a HER2 score 2+ by IHC when stratified by HER2 gene copy number. Our data suggest that ASCO/CAP HER2 Group 2 carcinomas should be evaluated further with respect to eligibility for HER2 targeted therapy.
Texto completo:
1
Base de datos:
MEDLINE
Asunto principal:
Neoplasias de la Mama
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Receptor ErbB-2
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Dosificación de Gen
Tipo de estudio:
Diagnostic_studies
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Etiology_studies
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Guideline
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Incidence_studies
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Observational_studies
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Prognostic_studies
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Risk_factors_studies
Límite:
Female
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Humans
Idioma:
En
Revista:
Br J Cancer
Año:
2021
Tipo del documento:
Article
País de afiliación:
Reino Unido