Author of

• 11543

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  P2.06 - Poster Session 2 - Prognostic and Predictive Biomarkers (ID 165)

  • Event: WCLC 2013
  • Type: Poster Session
  • Track: Biology
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/29/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

  • 11558

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    P2.06-015 - Novel plasma proteins associated with prognosis in malignant pleural mesothelioma (ID 1337)

    09:30 - 09:30  |  Author(s): X. Song
    • Abstract

    Background
    The search for novel biomarkers to define more successful and individual treatment approaches represent an important challenge for those involved in the care for patients with malignant pleural mesothelioma (MPM). In this exploratory study, we have systematically investigated the proteins present in plasma of MPM patients and correlated their levels with disease outcomes.

    Methods
    Plasma samples from twelve MPM patients (6 ‘short-’ and 6 ‘long-term’ survivors from parallel phase II studies investigating thalidomide) were used for proteomic analyses. Our series included samples from 9 patients with epithelial MPM and 3 patients with biphasic MPM. Plasma samples were immuno-depleted of the 14 most abundant proteins prior to labelling for isobaric tag for relative and absolute quantitation (iTRAQ) analysis using mass spectrometry. The most promising candidates and mesothelin were chosen for selected reaction monitoring mass spectroscopy (SRM-MS) quantification and enzyme-linked immunosorbent assay (ELISA) validation. Statistical analyses using T-Test of peak areas were used to identify proteins that were differentially expressed between the short- and long-term survivor groups.

    Results
    Median survival of short- and long-term survivors (1.2 and 38.3 months, respectively) differed significantly (p = 0.001). This was also the case for the neutrophil-to-lymphocyte ratio (NLR) that was significantly higher in the group of short-term survivors (p=0.03). Other baseline characteristics did not reveal major differences between the short- and long-term survivors. The total number of proteins identified was 226 (1% false discovery rate) in iTRAQ. A number of those were found to be differentially expressed between short- and long-term survivors (≥1.2-fold change; p≤0.05) by iTRAQ: selenoprotein P; tetranectin; insulin-like growth factor-binding protein 2 (IBP2); osteonectin (SPARC); platelet basic protein (CXCL7); and attractin. Mesothelin was assessed to validate the proteomic methodology: SRM-MS quantification was highly correlated with the MESOMARK ELISA values with a Pearson correlation of 0.82 (p=0.001). SRM-MS quantification revealed that the concentrations of attractin (p=0.02), tetranectin (p=0.003) and selenoprotein P (p=0.001) were higher in long-term survivors. In contrast, there was a trend for an increase in the concentration of SPARC (p=0.32), IBP2 (p=0.12) and CXCL7 (p=0.19) to be correlated with shorter survival. Furthermore, quantification by ELISA demonstrated an association between long survival and low concentration of SPARC (p=0.07) as well as high tetranectin (p=0.13).

    Conclusion
    We have demonstrated the feasibility of using the iTRAQ and SRM-MS proteomic techniques to investigate potential prognostic protein markers in plasma of MPM patients. Potential prognostic biomarkers worthy of further studies include SPARC and tetranectin and we plan to validate these in a larger clinical cohort.