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MINI 27 - Biology and Other Issues in SCLC (ID 152)
- Event: WCLC 2015
- Type: Mini Oral
- Track: Small Cell Lung Cancer
- Presentations: 1
MINI27.04 - PD-L1 and C-MET Expression and Survival in Patients with Small Cell Lung Cancer (ID 2354)
16:45 - 18:15 | Author(s): Y. Xu
Blocking the interaction between the programmed cell death (PD)-1 protein and one of its ligands, PD-L1, has been reported to have impressive antitumor responses. PD-L1 interaction is a major pathway often hijacked by tumors to suppress immune control. Studies on the roles of PD-L1 in non-small cell lung cancer (NSCLC) are controversial, but its roles in small cell lung cancer (SCLC) are rare and unclear. Moreover, MET/HGF axis seems to be the other one of the most aberrant signaling pathways in SCLC. The aim of our study was to investigate the expression and prognostic roles of PD-L1 and cellular-mesenchymal to epithelial transition factor(c-MET) in SCLC.
The expression of PD-L1 and c-MET were evaluated by immunohistochemical analysis in 83 specimens of SCLC, including 47 limited disease (LD) and 36 extensive disease(ED). Tumors with PD-L1 staining in over 5% of tumor cells were scored as positive for PD-L1 expression. Tumors with c-MET strong staining in at least 10% or weak to moderate staining in at least 40% of tumor cells were scored as positive for c-MET expression. Survival analysis was performed using the Kaplan-Meier method.
The positive rate of PD-L1 and c-MET in SCLC specimens were 51.8% and 25.3% respectively. The higher expression level of PD-L1 in tumor specimens was significantly correlated with a limited disease (LD) stage (p=0.004), a normal serum LDH level (p=0.031), and a normal NSE level (p=0.005). No association was found between the expression level of c-MET and PD-L1 , or c-MET expression with the other clinical characteristics of SCLC patients. SCLC patients with PD-L1-positive tumors showed significantly longer overall survival (OS) than those with PD-L1-negative (median OS, 17.0 vs 9.0, p=0.018). SCLC patients with positive c-MET expression showed a trend of shorter overall survival (12.0 vs 15.0, p=0.186). But sub-analysis of Limited disease (LD)-stage patients showed that the c-MET negative group had a longer OS (25.0 vs 14.0; p=0.011). Multivariate analyses revealed that LD stage, good performance status but except for PD-L1 or c-MET immunoreactivity were independently predictive of better OS.
In patients with SCLC, expression of PD-L1 was positively correlated with a LD stage and better OS, but was not an independently predictive factor of outcome. High expression level of c-MET revealed a trend of worse outcome. It was associated with poor prognosis especially in LD-Stage patients.
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