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  P3.06 - Poster Session 3 - Prognostic and Predictive Biomarkers (ID 178)

  • Event: WCLC 2013
  • Type: Poster Session
  • Track: Biology
  • Presentations: 2
  • Moderators:
  • Coordinates: 10/30/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

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    P3.06-007 - Clinical feasibility study of a novel sorting system for detecting EGFR mutations from captured circulating tumor cells in patients with lung cancer (ID 1046)

    09:30 - 09:30  |  Author(s): Y. Koh
    • Abstract

    Background
    Circulating tumor cells (CTCs) are cells that originate from a primary solid tumor and are found transiting the circulatory system. CTCs are expected to provide useful clinical information on biology of their primary, as ”liquid biopsy.” We have developed a novel cell-sorting system equipped with a disposable microfluidic chip (On-chip Sort, On-Chip Biotechnologies, Tokyo, JAPAN). At American Association for Cancer Reseach meeting 2013, we previously reported about its CTCs enumeration capability when performed in a clinical setting. Currently, On-chip Sort enables recovery of more CTCs than conventional cell sorting systems for further characterization.

    Methods
    In a preclinical study, PC-9 and H1975 human lung cancer cells harboring EGFR mutations (E746_A750del and L858R, T790M, respectively) were spiked into the blood from healthy donors. After samples were negatively enriched using anti-CD45-coated magnetic beads, the spiked cancer cells in the samples were captured by On-chip Sort. The captured tumor cells were subjected to mutation detection by ARMS/Scorpion PCR assay. A clinical feasibility study was then conducted in lung cancer patients harboring EGFR mutations.

    Results
    On-chip Sort performed recovery of the spiked PC-9 and H1975 cancer cells (5 cells in 4 ml of blood) in a preclinical experiment. Successively, we were able to detect the EGFR mutations from the captured cells. In a clinical feasibility study, 4 blood samples from lung cancer patients harboring EGFR mutation were collected and were evaluated. All the samples were successful in capturing CTCs by On-chip Sort. ARMS/Scorpion PCR assay detected the EGFR deletion mutation from two of the samples (50%).

    Conclusion
    The preclinical study and the results of the clinical feasibility study suggested the possibility of the On-chip Sort assay to detect EGFR mutations from peripheral blood of patients with lung cancer. Further investigation is going to be conducted to evaluate the correlation of EGFR mutations in captured CTCs and primary lesions.

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    P3.06-012 - Pharmacogenetic study of Japanese patients with advanced non-squamous non-small cell lung cancer treated with pemetrexed plus cisplatin (ID 1407)

    09:30 - 09:30  |  Author(s): Y. Koh
    • Abstract

    Background
    Pemetrexed (PEM) inhibits multiple enzymes in the folate (F) pathway. Several studies show that genetic polymorphisms in these enzymes influence the efficacy and toxicity of PEM. We aimed to investigate the relationship between genetic polymorphisms associated with the F pathway and clinical outcomes of Japanese patients with advanced non-squamous non-small cell lung cancer (NSQ-NSCLC) treated with PEM plus cisplatin (CIS).

    Methods
    We analyzed 34 polymorphisms in 14 genes associated with the F pathway in NSQ-NSCLC patients treated with PEM plus CIS: ABCC11, ADA, ATIC, DHFR, ERCC1, FPGS, GGH, MTHFD1, MTHFR, MTR, MTRR, SHMT1, SLC19A1, and TYMS. These polymorphisms were compared with clinical outcomes such as response, toxicity, and progression-free survival (PFS) using Pearson’s χ[2] test and the log-rank test.

    Results
    All 56 patients were Japanese, with a median age of 62 years; 57.1% were male, 96.4% had an Eastern Cooperative Oncology Group Performance Status of 0–1, 96.4% had stage IV disease, and 94.6% had adenocarcinoma. The response rate, disease control rate, and median PFS were 32.2%, 78.6%, and 4.7 months, respectively. Of the 38 polymorphisms tested, none were associated with response or toxicity, but 2 single nucleotide polymorphisms (SNPs) (in the gamma-glutamyl hydrolase [GGH 452C>T] and methionine synthase [MTR 2756A>G] genes) were significantly associated with PFS. Patients harboring the GGH-C452C variant had significantly longer PFS (5.6 vs 2.8 months; p < 0.0001) than those with the C452T or T452T variants. Further, patients harboring the MTR-A2756A variant had significantly longer PFS (5.3 vs 3.7 months; p = 0.036) than those with the A2756G variant. In addition, among patients with the GGH-C452C variant, those harboring the MTR-A2756A variant had significantly longer PFS (5.9 vs 4.3 months; p = 0.044) than those with the A2756G variant.

    Conclusion
    SNPs in GGH and MTR seem to predict differences in PFS in NSQ-NSCLC patients treated with PEM plus CIS, and a combination of these 2 SNPs may predict differences in PFS more accurately. These results should be validated in larger, adequately designed prospective studies.