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MO14 - Mesothelioma II - Surgery and Multimodality (ID 121)
- Event: WCLC 2013
- Type: Mini Oral Abstract Session
- Track: Mesothelioma
- Presentations: 1
MO14.07 - Elevated tumour expression of miR-210 is associated with short survival in malignant pleural mesothelioma patients undergoing extrapleural pneumonectomy (ID 1491)
10:30 - 12:00 | Author(s): M.B. Kirschner
Malignant pleural mesothelioma (MPM) is an aggressive cancer with a median survival of around one year and a 5 year survival rate of less than 10%. A selected group of patients with a potentially resectable tumour mass and good performance status may be considered for extrapleural pneumonectomy (EPP). However the results of this form of treatment are variable. Several prognostic markers have been explored to assist with patient selection including histological subtype, neutrophil-to-lymphocyte ratio (NLR), calretinin and microRNA miR-29c* expression in tumour tissue. In the present study we used microarray profiling to identify other microRNAs which might have the potential to serve as a prognostic biomarker.
The study used 60 formalin-fixed paraffin embedded (FFPE) tumour tissues from MPM patients who underwent EPP and had sufficient tumour for RNA extraction, a series which had been previously used to assess the prognostic value of the NLR. MicroRNA microarray profiling was performed on RNA from the 8 patients with longest (median: 53.7 months) and the 8 patients with shortest (median: 6.4 months) survival. Candidate microRNAs were selected on a basis of biological (>2-fold difference) and statistical (p<0.05) significance, and selected candidates were independently validated in the initial profiling samples using TaqMan assay-based microRNA-specific RT-qPCR. Levels of validated candidates were then assessed by RT-qPCR in 44 additional tumour samples. Overall survival (OS) was calculated from date of EPP and date of death or last follow-up, with patients still alive at last follow-up censored. The median relative expression level of each candidate was used as cut-off to determine high and low expression for examination using the Kaplan-Meier method. Individually significant (p<0.05) variables were entered into a multivariate model together with the established risk factors age, gender, histological subtype, NLR.
Microarray profiling identified 12 microRNAs with lower expression in long-term survivors and 4 microRNAs with higher expression in long-term survivors. None of the microRNAs with higher expression in long-term survivors could be validated using RT-qPCR. Of the microRNAs with lower expression in long-term survivors, miRs-30e, -93, -106b, -210, and -222 were validated by RT-qPCR in the same samples used for the profiling and found to be significantly different between long-term and short-term survivors. The expression levels of miR-30e and miR-210 showed a significant association with survival. MiR-30e: median OS of 24.2 months for low expression vs 13.3 months for high expression (p=0.03); miR-210: median OS of 24.2 months for low expression vs 13.7 months for high expression (p=0.008). In addition, both gender and histological subtype were significant prognostic factors using a univariate model. Multivariate analysis with age, gender, histological subtype, NLR and microRNA expression included as variables revealed that miR-210 was the only factor remaining significant (p= 0.006; hazard ratio: 0.41; 95% CI: 0.2-0.85).
This study has identified expression of miR-210 as a potential new prognostic factor for patients undergoing EPP. Further validation is needed, but this marker has the potential to assist in better selection of patients considered for radical surgery of MPM.