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M.E. Arcila



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    MINI 22 - New Technology (ID 134)

    • Event: WCLC 2015
    • Type: Mini Oral
    • Track: Biology, Pathology, and Molecular Testing
    • Presentations: 1
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      MINI22.02 - Clinically Adoption of MSK-IMPACT, a Hybridization Capture-Based next Generation Sequencing Assay, for the Assessment of Lung Adenocarcinomas (ID 2881)

      16:45 - 18:15  |  Author(s): M.E. Arcila

      • Abstract
      • Presentation
      • Slides

      Background:
      Mutation analysis plays a central role in the management of lung adenocarcinomas (LUAD). The use of multiple single gene or mutation specific assays, broadly adopted in many laboratories to detect clinically relevant genomic alterations, often leads to delays if sequentially performed, tissue exhaustion, incomplete assessment and additional biopsy procedures. Comprehensive assays using massively parallel “next-generation” sequencing (NGS) offer a distinct advantage when addressing the increased testing needs of genotype-based therapeutic approaches. Here we describe our experience with a 410 gene, clinically validated, hybrid-capture-based NGS assay applied to testing of LUAD.

      Methods:
      Consecutive LUAD cases submitted for routine mutation analysis within a 1 year period were reviewed. Unstained slides of formalin fixed, paraffin embedded tissue were received for each case (range 15-20 slides/case). Corresponding H&E stained slides were reviewed and cell counts were performed in a subset of cases with limited material to establish minimal tissue requirements. Testing was performed by a laboratory-developed custom hybridization-capture based assay (MSK-IMPACT) targeting all exons and selected introns of 410 key cancer genes (J Mol Diagn 17:251-264, 2015). Barcoded libraries from tumor / normal pairs were captured and sequenced on an Illumina HiSeq 2500 and analyzed with a custom analysis pipeline.

      Results:
      A total of 469 specimens were received for comprehensive testing (98 cytology samples, 239 needle biopsies, 132 large biopsies/resections) of which 93% (436/469) were successfully tested. Thirty four cases (7%, 34/469) failed due to very low tumor content or low DNA yield. Cell counts for failed samples averaged 239 cells / slide (range 10-270) while all successfully tested had over 1,000 cells / slide each. Failure rate was similar for cytologies and biopsies. An average of 10 genomic alterations were detected per patient (range 1-96). The most frequently mutated genes were TP53, EGFR, KRAS, KEAP1 and STK11. Copy number gains of NKX2-1 and EGFR genes and CDKN2A loss were most common. EGFR mutations and ALK fusions were detected in 28% and 4% of cases, respectively. Among the 299 EGFR / ALK WT cases, MSK-IMPACT uncovered targetable genomic alterations that would have remained undetected through focused EGFR/ALK testing alone. These included fusions in RET (10) and ROS1 (13), mutations in ERBB2 (11) and BRAF (19) and amplifications in MET (12, unrelated to EGFR), MDM2 (26) and CDK4 (20) among others. The higher than expected rates of RET and ROS1 fusions are related to enrichment of previously tested cases known to be negative for other driver alterations.

      Conclusion:
      Comprehensive hybrid-capture based NGS assays such as MSK-IMPACT are an efficient testing strategy for LUAD across sample types. This upfront broad approach enables more optimal patient stratification for treatment by targeted therapeutics.

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    P1.02 - Poster Session/ Treatment of Localized Disease – NSCLC (ID 209)

    • Event: WCLC 2015
    • Type: Poster
    • Track: Treatment of Localized Disease - NSCLC
    • Presentations: 1
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      P1.02-008 - Diagnostic Molecular Testing in Multiple Lung Cancers (ID 3149)

      09:30 - 17:00  |  Author(s): M.E. Arcila

      • Abstract
      • Slides

      Background:
      Multiple lung cancers (MLCs) are determined using the Martini-Melamed clinical criteria, and comprehensive pathologic assessment. The underlying biology for why MLCs develop is not known. Herein, we evaluate clinicopathologic data for patients with MLCs, and report clonality between MLC lesions using diagnostic molecular testing.

      Methods:
      After IRB approval, we conducted a retrospective review of all patients who underwent an R0 resection for stage IA-IIIA LC from 2008-2013 in our institution. Patients with carcinoid tumors, adenocarcinoma-in-situ, multiple ground-glass opacities, intrapulmonary metastases, and cancers not originating from the lung, were excluded. MLCs were defined using Martini-Melamed criteria, and comprehensive pathologic assessment. Clinico-pathologic data was collected for patients with MLCs, including available diagnostic molecular data from sizing assays, Sanger sequencing and mass spectrometry genotyping (Sequenom).

      Results:
      2352 pts were identified: one LC (n=2238), recurrent LC (n=348), MLC (n=113). In patients with MLCs, adenocarcinoma histology (n=97) was associated with improved OS (p=0.049) compared to squamous histology (n=13, other n=3). Paired diagnostic molecular pathology was available in 51 patients with adequate tissue from MLCs. MLC pairs stratified by mutation type are depicted in Table 1. In 49 patients, both MLCs were adenocarcinomas (20= extended panel: sizing assays/Sanger sequencing/Sequenom, 29=limited panel: EGFR/KRAS sizing assay/Sanger sequencing): 51% (n=25/49) had concordant molecular results, suggesting a common tumor clone, and 49% (n=24/49) had discordant results. In 1 patient, one MLC was an adenocarcinoma and the other was a squamous carcinoma, and had discordant molecular results by limited panel testing. In 1 patient, both MLCs were squamous carcinomas, and had concordant molecular results by limited panel testing. In patients where MLCs both had a KRAS mutation (n=11), 3 pairs had the same mutation (KRAS G12C, KRAS G12D, KRAS G12F), and 8 had different mutations. Table 1: Multiple Lung Cancer: Molecular DataFigure 1



      Conclusion:
      Martini-Melamed criteria and comprehensive pathologic assessment, are currently used to diagnose MLCs. Assuming separate MLC lesions harbor distinct molecularly defined clones, paired molecular testing using limited panels is not sufficient to diagnose MLCs. Concordant molecular profiles do not necessarily define whether a lesion is an MLC or a metastatic lesion. Paired prospective testing of suspected MLC lesions including broader molecular tests such as DNA, RNA, protein expression and immune correlates, may advance our understanding of the biology of these tumors.

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    P2.04 - Poster Session/ Biology, Pathology, and Molecular Testing (ID 234)

    • Event: WCLC 2015
    • Type: Poster
    • Track: Biology, Pathology, and Molecular Testing
    • Presentations: 1
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      P2.04-050 - Basaloid Squamous Cell Cancers Arising from the Lung: Next Generation Sequencing Reveals PTCH1 Mutations in the Hedgehog Pathway (ID 3211)

      09:30 - 17:00  |  Author(s): M.E. Arcila

      • Abstract

      Background:
      Basaloid squamous cell lung cancers are a defined variant of non-small cell lung cancers associated with a high mitotic count and rapid clinical progression. Due to its morphologic similarities with basal cell carcinoma of the skin, distinguishing between the two can be difficult. We sought to define the molecular characteristics of basaloid squamous cell cancers that were clinically defined as possible lung primaries in an effort to aid in the diagnosis of this disease.

      Methods:
      We reviewed a total of 179 patients who were diagnosed with squamous cell lung cancers and had undergone tumor next generation sequencing at Memorial Sloan Kettering. Through the MSK-Integrated Mutation Profiling for Actionable Cancer Targets (MSK-IMPACT), the illumina HiSeq platform was used to detect 341 potentially actionable genetic alterations, including single base substitutions, indels, copy number alterations and selected gene fusions. Data on clinicopathologic characteristics, smoking history were reviewed, and their mutational profile described.

      Results:
      A total of 6 of 179 (2%) patients with squamous cell lung cancers were found to have basaloid features. Of the 6 patients with basaloid features, 5 (83%) were men, 2 (33%) were never-smokers, 6 (100%) were white Caucasians, 3 (50%) had resected lung specimens, and 2 (33%) presented with stage IV disease. Three cases (50%) had protein patched homolog 1 (PTCH1) mutations in the hedgehog pathway (H652Y, V1057splice, V579fs), identical to those found in basal cell carcinoma of the skin. Two of these patients had a history of basal cell carcinoma of the skin, raising the possibility of metachronous metastatic basal cell carcinoma of the skin. One patient had no such history of basal cell skin cancer.

      Conclusion:
      Basaloid squamous cell cancers that appear to arise from the lung frequently harbor PTCH1 mutations. Metachronous metastatic basal cell carcinoma of the skin needs to be considered as a possibility in patients with a history of superficial skin lesions. Patients diagnosed with these basaloid cancers that harbor PTCH1 mutations, whether from skin or lung origin, may benefit from hedgehog pathway inhibitors such as vismodegib.