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• 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

  • 11569

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    P2.06-026 - Association of New York-Esophageal Antigen-1 (NY-ESO-1) promoter methylation and survival in stage III non-small cell lung cancer (ID 2370)

    09:30 - 09:30  |  Author(s): A.C. Chueh
    • Abstract

    Background
    Cancer-Testis antigens (CTAs) are immunogenic molecules exclusively expressed in normal testes but with aberrant expression in up to 30% of NSCLC. NY-ESO-1, is a CTA whose expression is associated with poorer survival but improved response to chemotherapy.[1] The promoter regions for many CTA genes contain CpG islands which are predominantly methylated in most tissues. In cancer, hypomethylation of CTA gene promoters hsvr been shown to be determining factor for the frequent re-expression of these genes. Herein we sought to correlate NY-ESO-1 promoter methylation (PM) with protein expression in lung cancers and test whether methylation status can be used as a predictive and prognostic marker in NSCLC.

    Methods
    We reviewed the clinicopathological data for patients with pathological N2 NSCLC treated with surgical resection followed by either observation or adjuvant chemotherapy, if treated after 2004. Genomic DNA from formalin fixed paraffin embedded (FFPE) samples were purified and bisulfite converted according to the manufacturer’s (QIAGEN) instructions. Mutational status was determined in genomic DNA using Sequenom's Oncocarta panel v1.0. Tumour samples were cut and stained with NY-ESO-1 antibody (E978). Previously described protocols for methylation-specific NY-ESO-1 primers[2] and beta-actin[3] control probes were used. Using real-time quantitative methylation-specific polymerase chain reaction (qMS-PCR), the level of NY-ESO-1 methylation was determined and expressed as the ratio of methylated to unmethylated molecules (M/UM). We used a cut-off fold-difference of 5 (Log2, M/UM) to separate tumour samples into hypomethylated and hypermethylated groups. Survival estimates were obtained using the Kaplan-Meier method. Comparison across groups was performed using the Chi-squared or Fisher's test.

    Results
    NY-ESO-1 PM MS-PCR was successful in 92/100 (92%) of specimens. NY-ESO-1 was hypermethylated in 86% (79/92) of samples. Age, smoking history, gender, histology and oncogenic mutations were not associated with presence of NY-ESO-1 PM. NY-ESO-1 hypomethylation was inversely associated with protein expression (p<0.0001). In multivariate analysis, hypomethylation of the NY-ESO-1 promoter was an independent poorer prognostic marker in patients not treated with chemotherapy (HR 2.97, 95%CI 1.06-8.29, p=0.038), after adjusting for age, gender, stage IIIA/B and histology. Conversely, in patients treated with chemotherapy there were no differences in survival associated with NY-ESO-1 PM, suggesting hypomethylated tumours remain chemosensitive.

    Conclusion
    NY-ESO-1 hypomethylation was an independent adverse prognostic marker in patients not treated with chemotherapy. Given their poorer outcome, association with chemosensitivity and known immunogenicity, CTAs may make attractive targets for immunotherapy, demethylating agents and immune checkpoint inhibition. References 1.John et al. PLOS One, In press. 2.James et al. Oncogene 2006. 3.Eads et al. Cancer Res 2001. .