title: Reliable Entity Subtyping in Non-small Cell Lung Cancer by Matrix-assisted Laser Desorption/Ionization Imaging Mass Spectrometry on Formalin-fixed Paraffin-embedded Tissue Specimens.
abstract: Histopathological subtyping of non-small cell lung cancer (NSCLC) into adenocarcinoma (ADC), and squamous cell carcinoma (SqCC) is of utmost relevance for treatment stratification. However, current immunohistochemistry (IHC) based typing approaches on biopsies are imperfect, therefore novel analytical methods for reliable subtyping are needed. We analyzed formalin-fixed paraffin-embedded tissue cores of NSCLC by Matrix-assisted laser desorption/ionization (MALDI) imaging on tissue microarrays to identify and validate discriminating MALDI imaging profiles for NSCLC subtyping. 110 ADC and 98 SqCC were used to train a Linear Discriminant Analysis (LDA) model. Results were validated on a separate set of 58 ADC and 60 SqCC. Selected differentially expressed proteins were identified by tandem mass spectrometry and validated by IHC. The LDA classification model incorporated 339 m/z values. In the validation cohort, in 117 cases (99.1%) MALDI classification on tissue cores was in accordance with the pathological diagnosis made on resection specimen. Overall, three cases in the combined cohorts were discordant, after reevaluation two were initially misclassified by pathology whereas one was classified incorrectly by MALDI. Identification of differentially expressed peptides detected well-known IHC discriminators (CK5, CK7), but also less well known differentially expressed proteins (CK15, HSP27). In conclusion, MALDI imaging on NSCLC tissue cores as small biopsy equivalents is capable to discriminate lung ADC and SqCC with a very high accuracy. In addition, replacing multislide IHC by an one-slide MALDI approach may also save tissue for subsequent predictive molecular testing. We therefore advocate to pursue routine diagnostic implementation strategies for MALDI imaging in solid tumor typing.
authors.affiliation: From the ‡Institute of Pathology, University Heidelberg, 69120 Heidelberg, Germany; mark.kriegsmann@med.uni-heidelberg.de.
authors.forename: Mark
authors.initials: M
authors.lastname: Kriegsmann
authors.affiliation: §Proteopath GmbH, 54296 Trier, Germany.
authors.forename: Rita
authors.initials: R
authors.lastname: Casadonte
authors.affiliation: §Proteopath GmbH, 54296 Trier, Germany; ¶Center for Histology, Cytology and Molecular Diagnostics, 54296 Trier, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Kriegsmann
authors.affiliation: ‖Department of Thoracic Surgery, Thoraxklinik at Heidelberg University, 69126 Heidelberg, Germany.
authors.forename: Hendrik
authors.initials: H
authors.lastname: Dienemann
authors.affiliation: From the ‡Institute of Pathology, University Heidelberg, 69120 Heidelberg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Schirmacher
authors.affiliation: **SCiLS GmbH, 28359 Bremen, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Hendrik Kobarg
authors.affiliation: ‡‡Institute of Pathology, Technical University Munich (TUM), 81675 Munich, Germany.
authors.forename: Kristina
authors.initials: K
authors.lastname: Schwamborn
authors.affiliation: From the ‡Institute of Pathology, University Heidelberg, 69120 Heidelberg, Germany; §§German Cancer Consortium (DKTK).
authors.forename: Albrecht
authors.initials: A
authors.lastname: Stenzinger
authors.affiliation: From the ‡Institute of Pathology, University Heidelberg, 69120 Heidelberg, Germany; ¶¶Translational Lung Research Centre Heidelberg, Member of the German Centre for Lung Research.
authors.forename: Arne
authors.initials: A
authors.lastname: Warth
authors.affiliation: From the ‡Institute of Pathology, University Heidelberg, 69120 Heidelberg, Germany; ‡‡Institute of Pathology, Technical University Munich (TUM), 81675 Munich, Germany; §§German Cancer Consortium (DKTK); ‖‖National Center for Tumor Diseases (NCT), 69120 Heidelberg, Germany.
authors.forename: Wilko
authors.initials: W
authors.lastname: Weichert
mesh_terms: D000230:Adenocarcinoma / Q000145:classification / Q000378:metabolism / Q000473:pathology*; D000077192:Adenocarcinoma of Lung; D014408:Biomarkers, Tumor / Q000032:analysis*; D002289:Carcinoma, Non-Small-Cell Lung / Q000145:classification* / Q000378:metabolism / Q000473:pathology; D016002:Discriminant Analysis; D055088:Early Detection of Cancer; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008175:Lung Neoplasms / Q000145:classification* / Q000378:metabolism / Q000473:pathology; D016612:Paraffin Embedding; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry; D046888:Tissue Array Analysis / Q000379:methods; D016707:Tissue Fixation
chemical_list: D014408:Biomarkers, Tumor