Eren OC, Mericoz CA, Bozkurtlar E, Bulutay P, Baygul A, Kulac I. Novel ALK immunohistochemistry assay (clone OTI1A4, Dako) is a sensitive, reliable marker for identifying ALK rearrangements in lung adenocarcinomas: A validation study.
Am J Clin Pathol 2024;
161:71-82. [PMID:
37681660 PMCID:
PMC10765139 DOI:
10.1093/ajcp/aqad111]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Accepted: 08/04/2023] [Indexed: 09/09/2023] Open
Abstract
OBJECTIVES
We present the first study validating the recent Dako ALK assay (clone OTI1A4, in vitro diagnostic) for detecting ALK rearrangements in lung adenocarcinoma.
METHODS
Lung adenocarcinoma cases between 2011 and 2023 were retrospectively collected to create a cohort of 203 samples. Cases were stained with Dako ALK OTI1A4 and Ventana ALK D5F3 and reviewed by 3 pathologists independently. Correlation between assays, including their sensitivity and specificity, was evaluated.
RESULTS
The cohort (n = 203) consisted of resections, core needle biopsies, and cell blocks. Agreement between Dako ALK OTI1A4 and Ventana ALK D5F3 assays was "almost perfect," with κ = 0.89. The sensitivity and specificity of the Dako ALK OTI1A4 assay were 93.3% and 96%, respectively, in a subgroup of 55 molecularly confirmed cases (n = 30 with and n = 25 without ALK rearrangement).
CONCLUSIONS
Immunohistochemistry-based assays provide a valid and reasonably priced alternative, especially in settings where molecular confirmatory tests are neither offered nor accessible. Given high interassay and molecular concordance, we propose that the novel Dako OTI1A4 assay can be reliably used to identify cases with ALK rearrangement.
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