Discrepancies between FISH and immunohistochemistry for assessment of the ALK status are associated with ALK 'borderline'-positive rearrangements or a high copy number: a potential major issue for anti-ALK therapeutic strategies.
Ann Oncol
; 26(1): 238-244, 2015 Jan.
Article
em En
| MEDLINE
| ID: mdl-25344360
ABSTRACT
BACKGROUND:
Patients with advanced lung adenocarcinomas expressing ALK rearrangements are highly responsive to crizotinib, a dual ALK/c-MET inhibitor. Immunohistochemistry (IHC) is an easy clinically and routinely applicable cost-effective assay for ALK, c-MET and ROS1 protein expression for potential treatment with crizotinib. The purpose of this study was to evaluate the percentage and the pattern of ALK-rearranged cells, the variation in the native ALK copy number, as well as ALK, c-MET and ROS1 protein expression, and their significance on outcome of crizotinib-treated lung adenocarcinoma patients. PATIENTS ANDMETHODS:
Consecutive lung adenocarcinoma specimens (n = 176) 'double-negative' (wild-type EGFR and KRAS) were tested for ALK rearrangements/copy number alterations and for ALK, c-MET and ROS1 protein expression using automated standardized protocols. Preliminary data on the outcome of crizotinib-treated patients were recorded.RESULTS:
FISH analysis identified 26/176 (15%) cases with ALK rearrangements. Seven cases had discordant results between the ALK FISH and IHC. Five cases with discordant FISH-positive/IHC-negative revealed FISH 'borderline' positivity (15%-20%). Three cases overexpressed c-MET and responded to crizotinib, and two cases with ALK-'borderline' rearranged cells only, not associated with c-MET expression, progressed under crizotinib. Two cases with discordant FISH-negative/IHC-positive revealed ALK gene amplification without associated c-MET or ROS1 protein expression.CONCLUSIONS:
The discrepancies observed between the IHC and FISH data revealed unexpected biological events, rather than technical issues, which potentially can have a strong impact on the therapeutic strategy with crizotinib.Palavras-chave
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Base de dados:
MEDLINE
Assunto principal:
Adenocarcinoma
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Imunofluorescência
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Hibridização in Situ Fluorescente
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Receptores Proteína Tirosina Quinases
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Neoplasias Pulmonares
Tipo de estudo:
Guideline
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Prognostic_studies
/
Risk_factors_studies
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
Ano de publicação:
2015
Tipo de documento:
Article