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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
MO12.11 - The predictive role of common BIM deletion polymorphism and BIM expression on the EGFR-TKI therapy in never-smoking lung adenocarcinoma (ID 2161)
10:30 - 12:00 | Author(s): S.R. Goo
The BCL-2 homology domain 3 (BH3)-only protein, B-cell lymphoma 2 interacting mediator of cell death (BIM) is a potent pro-apoptotic protein. Recent data suggest that pretreatment BIM level may predict responsiveness to EGFR-TKI in EGFR-mutant non-small cell lung cancer (NSCLC). In addition, a common BIM deletion polymorphism contributes to the heterogeneity of response to EGFR-TKI in EGFR-mutant NSCLC. We investigated whether BIM expression and BIM deletion polymorphism (BIM-DEL) are predictive for response rate (RR) and progression-free survival (PFS) to EGFR-TKI therapy in never-smoking lung adenocarcinoma (NSLA).
We analyzed EGFR mutation status by Sanger sequencing, BIM-DEL genotyping by polymerase-chain reaction and BIM expression by immunohistochemistry using archival tissues or blood from 203 patients who participated in the FIRST-SIGNAL trial (1[st] line gefitinib vs. Gemcitabine/cisplatin in advanced NSLA).
EGFR mutation test, BIM-DEL genotyping and BIM-IHC analysis were available in 82, 126 and 60 patients, respectively. Forty-five (55%) patients had EGFR mutations, 22 (18%) showed BIM-DEL and 22 (37%) showed negative BIM expression. BIM expression was significantly associated with EGFR mutation status; more patients with EGFR-mutant NSCLC showed negative BIM expression (48% vs. 21%, P=0.030). BIM-DEL was not associated with EGFR mutation status or BIM expression. Among 181 patients who received EGFR-TKI as 1[st] or 2[nd]-line therapy, EGFR mutation, BIM-DEL and BIM expression data were available in 74, 11, 56 patients, respectively. EGFR mutation was predictive for higher RR (66% vs. 15%, P<.001) and longer PFS (4.5 vs. 1.9 months, P=.061) to EGFR-TKI therapy. Negative BIM expression also showed a trend toward higher RR (68% vs. 42%, P=.061) and longer PFS (6.9 vs. 2.3 months, P=.233) with EGFR-TKI. However, BIM-DEL was not predictive for RR (41% vs. 47%, P=.645) or PFS (3.5 vs. 3.7 months, P=.892) to EGFR-TKI.
Both BIM-DEL and BIM expression were not predictive for responsiveness to EGFR-TKI in NSLA. The trend between negative BIM expression and favorable response to EGFR-TKI may be resulted from higher frequency of EGFR mutation in these patients.
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