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  P3.09 - Pathology (Not CME Accredited Session) (ID 975)

  • Event: WCLC 2018
  • Type: Poster Viewing in the Exhibit Hall
  • Track:
  • Presentations: 1
  • Moderators:
  • Coordinates: 9/26/2018, 12:00 - 13:30, Exhibit Hall

  • 27593

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    P3.09-16 - Transcriptome Profiling for Subtyping NSCLC: Off the Beaten Path(Ologist) (ID 13894)

    12:00 - 13:30  |  Author(s): Mie Konno
    • Abstract
    • Slides

    Background
    

    Histopathological distinction between non-small cell lung cancer subtypes is still relevant in the age of targeted therapy due to the relatively low number of patients with actionable molecular alterations such as EGFR mutations or ALK rearrangements in squamous cell carcinomas. In addition, for patients without these alterations, the choice of most effective chemotherapy regimens is often based upon non-squamous vs squamous cell histology. However, histopathology scoring typically requires resected or biopsied tissue to be fixed, sliced, stained, and subjectively scored by a pathologist. Here we endeavor to demonstrate that subtle variances in gene expression within NSCLC patient samples can be used to classify the cancer subtype with a high degree of accuracy to pathology classification.

    a9ded1e5ce5d75814730bb4caaf49419 Method
    

    RNA extracted from 46 resected NSCLC cases (34 stage IIA/B, 12 stage IIIA/B; primarily adenocarcinomas and squamous cell carcinomas) were profiled using a transcriptome microarray platform (Illumina) and analyzed and compared to normal tissue using several Bioconductor R package pathway analysis tools and DAVID Bioinformatics Resources 6.8. Expression profiles were grouped by principle component score in a blinded manner.

    4c3880bb027f159e801041b1021e88e8 Result
    

    Clustering samples based on the top 10% most variable genes resulted in a highly accurate separation of adenocarcinoma samples and squamous cell carcinoma samples, with only one case of squamous cell carcinoma being misclassified as adenocarcinoma. The altered pathways that differentiated these samples included p53 signalling and PI3K-Akt signaling pathways, Cell adhesion molecules (CAM), ECM-receptor interactions, Wnt signalling and several other key pathways.

    8eea62084ca7e541d918e823422bd82e Conclusion
    

    Due to the successes of targeted therapeutic approaches, evaluating patient biopsies or other samples for EFGR mutations and ALK rearrangements are currently the standard of care for advanced-stage NSCLC. Immunohistochemical staining for the purposes of subtyping NSCLC can aid in developing treatment strategies for patients without these molecular alterations, but this can significantly reduce the quantity of tissue available for subsequent molecular tests. Based on our data, we believe that expression variances in a relatively small pool of genes and pathway analysis is sufficient to accurately predict the subtype of NSCLC, or at least narrow the number of cases requiring input from a pathologist to a small number of more difficult cases.

    6f8b794f3246b0c1e1780bb4d4d5dc53

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