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Inconsistent results in the analysis of ALK rearrangements in non-small cell lung cancer
Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology.
Lund Univ, Div Oncol & Pathol, Dept Clin Sci Lund, Lund, Sweden; Reg Labs Reg Skane, Dept Pathol, SE-22185 Lund, Sweden.
TU Dortmund Univ, Dept Stat, Dortmund, Germany.
Dortmund TU, Leibniz Res Ctr Working Environm & Human Factors, Dortmund, Germany.
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2016 (English)In: BMC Cancer, ISSN 1471-2407, E-ISSN 1471-2407, Vol. 16, 603Article in journal (Refereed) Published
Abstract [en]

Background: Identification of targetable EML4-ALK fusion proteins has revolutionized the treatment of a minor subgroup of non-small cell lung cancer (NSCLC) patients. Although fluorescence in situ hybridization (FISH) is regarded as the gold standard for detection of ALK rearrangements, ALK immunohistochemistry (IHC) is often used as screening tool in clinical practice. In order to unbiasedly analyze the diagnostic impact of such a screening strategy, we compared ALK IHC with ALK FISH in three large representative Swedish NSCLC cohorts incorporating clinical parameters and gene expression data.

Methods: ALK rearrangements were detected using FISH on tissue microarrays (TMAs), including tissue from 851 NSCLC patients. In parallel, ALK protein expression was detected using IHC, applying the antibody clone D5F3 with two different protocols (the FDA approved Ventana CDx assay and our in house Dako IHC protocol). Gene expression microarray data (Affymetrix) was available for 194 patients.

Results: ALK rearrangements were detected in 1.7% in the complete cohort and 2.0% in the non-squamous cell carcinoma subgroup. ALK protein expression was observed in 1.9% and 1.5% when applying the Ventana assay or the in house Dako protocol, respectively. The specificity and accuracy of IHC was high (>99%), while the sensitivity was between 69% (Ventana) and 62% (in house Dako protocol). Furthermore, only 67% of the ALK IHC positive cases were positive in both IHC assays. Gene expression analysis revealed that 6/194 (3%) tumors showed high ALK gene expression (≥6AU) and of them only three were positive by either FISH or IHC.

Conclusion: The overall frequency of ALK rearrangements based on FISH was lower than previously reported. The sensitivity of both IHC assays was low, and the concordance between the FISH and the IHC assays poor, questioning current strategies to screen with IHC prior to FISH or completely replace FISH by IHC.

Place, publisher, year, edition, pages
2016. Vol. 16, 603
Keyword [en]
Anaplastic lymphoma kinase, non-small cell lung cancer, immunohistochemistry, fluorescence in situ hybridization
National Category
Cancer and Oncology
URN: urn:nbn:se:uu:diva-284591DOI: 10.1186/s12885-016-2646-xISI: 000381219600002PubMedID: 27495736OAI: diva2:921215
Swedish Cancer Society
Available from: 2016-04-19 Created: 2016-04-18 Last updated: 2016-09-15Bibliographically approved
In thesis
1. An integrative strategy for targeted evaluation of biomarker expression in non-small cell lung cancer
Open this publication in new window or tab >>An integrative strategy for targeted evaluation of biomarker expression in non-small cell lung cancer
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Despite improvements in therapy, the prognosis for non-small cell lung cancer (NSCLC) patients remains poor, and cure is only possible in localized tumors after surgical resection. A new generation of targeted cancer drugs has led to the expectation that lung cancer therapy can be significantly improved, but these drugs are today only an option in a small subset of NSCLC patients, and their effect is temporary. Therefore, the aim of this thesis was to characterize NSCLC in order to find new treatment targets and to evaluate biomarkers that further optimize therapy selection.

In Paper I, the expression of the potential treatment targets claudin 6 and claudin 18.2 were evaluated based on immunohistochemical- and gene expression analysis. High ectopic protein and gene expression were demonstrated for both claudins in small subgroups of NSCLC. Clinical trials using humanized monoclonal antibodies against both proteins are ongoing in other cancer forms and may be extended to NSCLC.

In Paper II, the prognostic impact of the inflammatory mediator cyclooxygenase 2 (COX-2) was evaluated. No prognostic significance was found in a meta-analysis incorporating gene expression data of 1337 NSCLC patients. Likewise, COX-2 protein expression in tumor cells was not associated with survival in two independent NSCLC cohorts. However, in one of the analyzed cohorts, higher COX-2 expression in the tumor stroma was associated with longer survival and may therefore be a subject for further investigation.

In Paper III, tumor and stromal COX-2 protein expression was examined in patients treated with the COX-2 inhibitor celecoxib in order to evaluate if COX-2 expression is a predictive biomarker for benefit of celecoxib therapy. Celecoxib did not prolong overall survival neither in the whole cohort nor in patients stratified according to COX-2 expression in tumor or stromal cells. Noteworthy, a tendency towards longer survival was again demonstrated in patients with high COX-2 stromal expression.

In Paper IV, the diagnostic methods for identification of ALK rearrangements were assessed in a large representative Swedish NSCLC population. Fluorescence in situ hybridization (FISH), as the diagnostic standard, was compared to two immunohistochemical assays. ALK gene expression levels were incorporated to supplement the molecular data. The frequency of ALK rearrangements was lower than previously reported. The different methods to detect the ALK fusion demonstrated overlapping results. However, the overlap was poor, so the methods cannot be regarded as interchangeable and should thereby be interpreted with caution when used in clinical diagnostics.

In summary, this thesis applied an integrative translational approach to characterize potential new treatment targets and to evaluate the detection of existing predictive biomarkers in NSCLC.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2016. 58 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine, ISSN 1651-6206 ; 1229
non-small cell lung cancer, prognostic biomarkers, predictive biomarkers, immunohistochemistry, gene expression, COX-2, claudin, ALK
National Category
Other Medical Sciences Cancer and Oncology
Research subject
Medical Science
urn:nbn:se:uu:diva-285844 (URN)978-91-554-9584-8 (ISBN)
Public defence
2016-06-11, Fåhraeussalen, Rudbecklaboratoriet, Dag Hammarskjöldsväg 20, Uppsala, 09:15 (English)
Available from: 2016-05-19 Created: 2016-04-19 Last updated: 2016-06-01

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Mattsson, JohannaLa Fleur, LinnéaPontén, FredrikKoyi, HirshBrandén, EvaBotling, JohanMicke, Patrick
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