ERBB2 amplification status in 67 salivary duct carcinomas assessed by immunohistochemistry, fluorescence in situ hybridization, and targeted exome sequencing.
Mod Pathol
; 35(7): 895-902, 2022 07.
Article
em En
| MEDLINE
| ID: mdl-34963694
ABSTRACT
Salivary duct carcinoma (SDC) is an aggressive salivary gland malignancy with poor survival. Approximately 30% SDC harbor HER2 amplification and response to trastuzumab has been reported. However, a systematic approach for HER2 status assessment in this tumor type has not been established. A total of 67 tumor samples were evaluated for HER2 protein overexpression or ERBB2 gene amplification using at least 2 methods:
immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), and/or targeted exome next-generation sequencing (NGS). NGS assessed ERBB2 copy number fold change (FC) and total copy number (TCN). HER2 status was first determined by IHC/FISH according to the 2018 ASCO/CAP breast cancer guidelines. FISH results, the "gold standard", were compared with the NGS results. All (15/15) IHC positive, 35% (6/17) equivocal, and no (0/19) IHC negative SDC were HER2 amplified by FISH. HER2 FISH signal/cell showed a good correlation with FC (Spearman correlation 0.708, R2 0.501, p < 0.0001) and TCN (Spearman correlation 0.763, R2 0.582, p < 0.0001). Receiver operating characteristics curve estimation showed an area under curve (AUC) of 0.975 for ERBB2 FC. FC cutoff of ≥1.8 corresponded to an accuracy of 95.2% for ERBB2 amplification (Youden's index 0.84, sensitivity 89.47%, specificity 100%). FC < 1.3 could be reliably classified as ERBB2 not amplified and FC ≥ 1.3 and <1.8 as equivocal. TCN estimation showed AUC of 0.981. TCN cutoff of >6.0 corresponded to an accuracy of 92% for HER2 amplification (Youden's index 0.81, sensitivity 81.2%, specificity 100%). TCN < 4 could be reliably classified as ERBB2 not amplified and TCN ≥ 4.0 and ≤6.0 as equivocal. FC and TCN were binarized with respective cutoffs of ≥1.8 and ≥6.0 and the proportion of agreement with FISH were 95% and 92%, respectively. The assessment of ERBB2 copy number by NGS is accurate and reliable with FC or TCN nearly equivalent to FISH in identifying HER2 amplified SDC.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Neoplasias das Glândulas Salivares
/
Carcinoma Ductal
Tipo de estudo:
Prognostic_studies
Limite:
Humans
Idioma:
En
Revista:
Mod Pathol
Assunto da revista:
PATOLOGIA
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
Estados Unidos