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MO12 - Prognostic and Predictive Biomarkers III (ID 96)
- Event: WCLC 2013
- Type: Mini Oral Abstract Session
- Track: Medical Oncology
- Presentations: 1
MO12.10 - Analysis of BIM Deletion polymorphism in Chinese Patients with NSCLC (ID 1083)
10:30 - 12:00 | Author(s): X. Yang
Drug resistance significantly weakens the effect of treatment. BIM deletion polymorphism has emerged as a potential drug resistant biomarker. This study aimed at assessing the correlation of BIM deletion with the outcome of Epidermal growth factor receptor tyrosine kinase inhibitors(EGFR-TKIs ) and chemotherapy in Chinese NSCLC patients
290 patients with advanced NSCLC who received EGFR-TKIs and chemotherapy were included in this retrospective study. BIM deletion polymorphism and EGFR mutations were detected by Polymerase Chain Reaction (PCR) and denaturing high-performance liquid chromatography (DHPLC) respectively.
BIM deletion polymorphism occurs commonly in Chinese NSCLC patients (15.5%, 45/290). No associations were observed between BIM deletion polymorphism with clinicopathology characteristics including sex, smoking and EGFR mutation status. BIM deletion polymorphism predicts shorter PFS in Chinese patients with EGFR-mutant NSCLC received EGFR-TKIs (6.69 vs 8.47months, P=0.023). Meanwhile, we found that BIM deletion polymorphism is an effective predictor of short PFS in individuals with EGFR-mutant NSCLC treated with pemetrexed contained chemotherapy (3.32vs5.30, P=0.012) or with second-/beyond-line Taxanes contained chemotherapy (1.53 vs 2.61months, P=0.025) However, In the EGFR-wild type group, the difference is not significant for the former two groups. patients with this deletion are prone to suffering serious adverse event (SAE) (4.5% vs. 15.6%, P=0.018). BIM deletion lacks for correlation with OS. (21.87vs21.90months, P=0.627), even in the EGFR-mutant group.
BIM deletion polymorphism occurs in 15.5% Chinese NSCLC patients. BIM deletion polymorphism is a drug resistance biomarker for TKIs and chemotherapy in NSCLC. BIM deletion possibly affects OS, but not a decisive factor.
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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
- Coordinates: 10/29/2013, 09:30 - 16:30, Exhibit Hall, Ground Level
P2.06-034 - Analysis of Sensitivity of Lung Squamous Carcinoma with EGFR Mutation to EGFR-TKIs and Resistant Mechanism (ID 2537)
09:30 - 16:30 | Author(s): X. Yang
Epidermal growth factor receptor (EGFR) gene variation is one common driver mutation in lung cancer. In lung adenocarcinoma, EGFR mutations are the powerful predictors to the efficacy of EGFR-TKIs. However, the phenomenon seemed to be inconsistent in lung squamous carcinoma. The present study aims to investigate the sensitivity of lung squamous cell carcinoma (SCC) harboring EGFR mutation to EGFR-TKIs, and explore the likely molecular mechanisms through constructing EGFR mutant lung SCC cell lines and analyzing the results transcriptomics.
This study retrospectively enrolled 91 patients with advanced lung SCC who received EGFR-TKIs in Beijing University Cancer Hospital. Denaturing high-performance liquid chromatography (DHPLC) and immunohistochemistry (IHC) were used for the detection of EGFR mutations and protein expressions of P63 and TTF-1, respectively. Stable cell lines were constructed through lipofectamine and confirmed by western-blot, soft agar cloning formation and tumoregeneity in nude mice. Cell titer Glo was used for cell number counting. RNASeq was used for the analysis of transcriptomics and related signaling pathways were screened in KEGG website. SPSS (17.0 version) was used for statistics.
The frequency of EGFR mutation was 16.2% (64/396) in lung SCC. In lung cancer patients with EGFR mutation, lung SCC patients accounted for 7% (64/863), commonly in male (71.9%), smoker (59.4%) and EGFR exon 19DEL (64.1%). In total 91 patients who received EGFR-TKIs, the objective response rate (ORR) and the disease control rate (DCR) were 11.0% (10/91) and 56.0% (51/91) respectively and the progression-free survival (PFS) and the overall survival (OS) were 2.9 months and 16.3 months. In terms of 60 patients who provided EGFR mutated status, 29 patients harbored EGFR mutation and the other 31 without EGFR mutation. The PFS of the subgroup with EGFR mutation after EGFR-TKIs showed prolonged trend compared with that of the subgroup without EGFR mutation, however, the statistics failed to amount to significant difference (2.4 months vs. 1.8 months, p=0.071). No statistical differences were observed in PFS ORR, DCR and OS between the two subgroups. IHC results demonstrated that most of lung SCC patients harboring EGFR mutation showed P63 positive and TTF-1 negative (15/18). We then constructed lung SCC cell lines with EGFR mutation (Beas-2B/EGFR 19DEL cell line and Beas-2B/EGFR 21L858 cell line), which showed resistant to erlotinib with the IC50 of 3.43±0.56μM和11.9±1.18μM. After the treatment of erlotinib, the mainly up-regulated signaling pathways included TGFβ pathway and hedgehog pathway, and RNA levels of some mesenchymal genes were also up-regulated.
Lung SCCs with EGFR mutation were not uncommon, who showed insensitivity and even resistance to EGFR-TKIs. The likely molecular mechanisms included TGFβ related epithelial-mesenchymal transition (EMT) and tumor stem cell like differentiation, and the upregulation of bone morphogenetic protein 4 (BMP4).