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C. Bell



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    Poster Display session (Friday) (ID 65)

    • Event: ELCC 2018
    • Type: Poster Display session
    • Track:
    • Presentations: 1
    • Moderators:
    • Coordinates: 4/13/2018, 12:30 - 13:00, Hall 1
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      30P - Feasibility of anti-ROS1 SP384 for detection of ROS1 protein (ID 433)

      12:30 - 13:00  |  Author(s): C. Bell

      • Abstract
      • Slides

      Background:
      Determination of ROS1 positivity in non-small cell lung cancer (NSCLC) is essential for appropriate identification of patients who may respond to ROS tyrosine kinase inhibitor therapy. ROS1 positivity is often clinically detected by fluorescence in situ hybridization (FISH). A ROS1 antibody that can detect ROS1 protein with high sensitivity, specificity, and consistency would allow for immunohistochemistry (IHC) screening for ROS1 positivity. Here, we present data on the feasibility of using VENTANA ROS1 (SP384) Rabbit Monoclonal Primary Antibody (anti-ROS1 SP384) for the detection of ROS1 protein.

      Methods:
      Anti-ROS1 SP384 has been optimized with VENTANA OptiView DAB IHC Detection Kit and on BenchMark IHC/ISH instruments. Anti-ROS1 SP384 was evaluated for sensitivity, specificity, and consistency of staining for the ROS1 protein. Sensitivity and specificity were assessed through immunoreactivity using tissue microarrays (TMAs) containing NSCLC (n = 40), cholangiocarcinoma (n = 64), melanoma (n = 90), 20 non-neoplastic tissue types, and additional 15 neoplastic tissues. The following parameters were assessed: percent target cell staining, overall intensity of target cell staining on a scale of 0–3 in 0.25 increments, and reactivity which is deemed as sample with >0% ROS1 staining. Consistency of anti-ROS1 SP384 staining was assessed on BenchMark GX, XT and ULTRA platforms and for 3 different antibody lots.

      Results:
      Anti-ROS1 SP384 exhibited high sensitivity and specificity in when staining TMAs containing a range of neoplastic and non-neoplastic tissues and when comparing the results to prevalence of ROS1 expression cited in the literature. The antibody showed expected expression of ROS1 in NSCLC, cholangiocarcinoma, melanoma, normal kidney tubules, and type II pneumocytes. The remaining cases included on the TMA were largely non-reactive. Staining performance of anti-ROS1 SP384 was consistent across 3 platforms and 3 antibody lots.

      Conclusions:
      Herein, we demonstrate that it is feasible to use anti-ROS1 SP384 to detect ROS1 protein due to the high sensitivity, specificity, and consistency of the antibody. Further studies are ongoing in previously characterized patient samples to assess antibody performance, clinical utility, and staining interpretation guidance.

      Clinical trial identification:


      Legal entity responsible for the study:
      Ventana Medical Systems, Inc.

      Funding:
      Ventana Medical Systems, Inc.

      Disclosure:
      I. Menzl, B. Richardson, C. Le, D. Smith, A.E. Hanlon Newell, G. Pate, R.S.P. Huang: Employee of Roche/Ventana Medical Systems and owns stock in Roche. C. Bell: Employee of Roche/Ventana Medical Systems.

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