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e23261Background: Programmed death-ligand 1 (PD-L1) expression on immunohistochemistry is associated with response to PD-1 blockade.However, the molecular mechanism and clinical significance of PD-...

e22045 Background: BCL2-like 11 (BIM) deletion polymorphism was reported to be an independent prognostic factor for shorter progression-free survival (PFS) in patients treated with epidermal growth...

11054 Background: Patients with EGFR-mutant lung adenocarcinoma develop acquired resistance to EGFR-TKI (TKI) in 10-16 months. About 50% of patients with acquired resistance to TKI have T790M mutat...

11052 Background: Germ line alterations in the proapoptotic protein BCL2-like 11 (BIM) can have a crucial role in how a tumor responds to treatment. To clarify the clinical usefulness of detecting BIM deletion polymorphism in non-small cell lung cancer (NSCLC) with positive epidermal growth factor receptor (EGFR) mutation we examined the prognosis in patients with or without the BIM changes. Methods: Seventy NSCLC patients with positive EGFR mutation treated with EGFR-tyrosine kinase inhibitor (EGFR-TKI) between January 2008 and January 2013 were enrolled in this study. BIM deletion polymorphism was analyzed by PCR in 58 peripheral blood samples, 24 formalin-fixed paraffin-embedded (FFPE) slides of surgical specimens (lung tissue in 20, brain tissue in 4), and 12 samples that included both blood and tissue specimens. We performed retrospective analyses on clinical characteristics, response rate and toxicity of EGFR-TKI, and estimated the prognosis in patients with or without BIM deletion polymorphism. Results: BIM deletion polymorphism was present in 13 of 70 patients (18.6%) with homozygous deletion in 1 and heterozygous deletion in 12. There was no discordance between the two types of samples among the 12 patients. There were no significant differences between patients with or without BIM deletion polymorphism on clinical characteristics, response rate to EGFR-TKI and incidence of EGFR-TKI toxicity. Patients with BIM deletion polymorphism showed significantly shorter PFS that in patients without BIM deletion polymorphism (median: 216 days vs. 430 days, p < 0.001). There was no significant difference in OS. In multivariate analyses using the Cox regression model, BIM deletion polymorphism (hazard ratio = 4.2, p< 0.001, 95% CI = 2.026-8.777) was identified as an independent factor for shorter PFS. Conclusions: BIM deletion polymorphism could be detected by PCR on peripheral blood samples and FFPE slides of surgical specimens. BIM deletion polymorphism has emerged as an independent prognostic factor for shorter PFS. Therefore, new treatment strategies should be established for patients with BIM deletion polymorphism.

e18127 Background: This study assessed correlations between the presence of circulating tumor cells (CTCs), detection of T790M in organs with metastases or circulating-free DNA (cfDNA), and prognosis in metastatic NSCLC patients with acquired resistance to EGFR-TKI. Methods: Metastatic NSCLC patients with activating EGFR mutations, who initially responded but subsequently experienced disease progression while on EGFR-TKI treatment, were defined as having ‘acquired resistance’. Blood samples were collected after development of such acquired resistance and CTCs were counted using the CellSearch system (Veridex). At the same time, T790M in affected organs or cfDNA was analyzed with cycleave real-time PCR assay and fragment analysis. Results: : Six men and 14 women with a mean age of 63.5 yrs (22-84) were enrolled. Histological subtypes were adenocarcinoma in 19 and squamous cell carcinoma in the remaining one. Clinical stages were stage IV in 14 and recurrence with distant metastases after surgical resection in 6. EGFR mutations in tumors at the primary site were G719C in 1, exon 19 deletion in 7, L858R in 10, and G791C + L858R in 2. CTCs were detected in 8 (40%). Numbers of CTCs (per 7.5 ml blood) were 1 in 4 cases, and 3, 4, 8, and 24 in 1 case each. Patients without CTCs survived significantly longer than those with CTCs (≥1 per 7.5 ml). Mean survival time from first detection of CTCs was 3.0 months in patients with CTCs and not reached in patients without CTCs (p < 0.001). T790M was detected in 6 cases (30%). T790M was found in 75% (n = 6/8) of patients without CTCs but in 0% (n = 0/12) of those with CTCs (p < 0.05). Conclusions: The presence of CTCs was correlated with poorly prognosis and lack of T790M in affected organs or cfDNA. The presence of CTCs was informative for distinguishing patients with or without T790M.

7595 Background: The purpose of this study was to assess the correlation between the numbers of circulating tumor cells (CTCs), prognosis and the positivity of blood plasma EGFR mutation in cell-fr...

18510 Background: The aim of this study was to assess the usefulness of induction chemoradiotherapy with carboplatin and docetaxel for non-small cell lung cancer (NSCLC) in stage III. Methods: The ...