Abstract 4148: MicroRNA biomarkers prognostic for disease-free and overall survival in stage I and II lung adenocarcinoma
Authors: Weiss Glen J. , Cherni Irene , Paquette Kim A. , Metpally Raghu , Whitsett Tim G. , Allen Jeffrey , Kim Seungchan , Hua Jianping , Tembe Waibhav D. , Lorenzo Carlos D. , Kurywchak Paul A. , Malik Mohsin , Raz Guy M. , Wagner Walter P. , Tran Nhan L. 
Published: August 2012

Abstract
Background: Approximately 50% of all non-small cell lung carcinoma (NSCLC) cases in the United States are adenocarcinoma histology. While definitive lung cancer resection offers a chance for cure in stage I and II NSCLC, up to 57% of patients will have disease relapse or metastatic disease within 5 years. A majority of the relapsed cases will take place within 2 years of definitive surgical resection. Thus, pathologic staging alone does not stratify patients for prognosis sufficiently. Identifying patients with aggressive versus indolent tumors would have critical implications for directing treatment and designing future clinical trials. We propose using microRNA (miRNA) for discovery and validation of prognostic biomarkers for stage I and II lung adenocarcinoma. Methods: For the Discovery Cohort, we identified treatment-naïve AJCC 7th edition stage I and II lung adenocarcinoma patient samples from 26 disease-free survivors (DFS) and overall survival (OS) at least 47 months and 14 patients with DFS and overall survival less than 23 months. Total RNA was extracted from formalin-fixed, paraffin-embedded (FFPE) samples. Differential miRNA array expression profiling between these two groups was assessed in the Discovery cohort on an 8x15 Agilent microarray printed with 886 miRNAs. Target miRNAs were selected based on minimum of 2-fold change in expression and Welch t-test p-value cut-off of &lt;0.05. For our Validation Cohort, qPCR assay of these individual miRNAs were measured from the 40 Discovery Cohort samples, as well as additional stage I and II lung adenocarcinoma patient samples (N=37 with DFS and OS&gt;47 months and N=12 with DFS and OS&lt;23 months), to confirm differential expression of target miRNAs. Fold-change values were generated using the ΔΔCt method. A PCR-based miRNA classifier was developed. Results: Microarray analysis of the Discovery Cohort revealed 7 miRNAs that were significantly under-expressed in lung adenocarcinoma tumor from patients with DFS and OS &lt;23 months. They included let-7a/b/c, miR-130a, -451, -29c, and -99a. PCR results in the Validation Cohort (total N=89) remained statistically significant for differential expression for all target miRNAs (p&lt;0.05) except miR-99a. A two miRNA PCR-based classifier using let-7c and miR-451 had the best performance with an accuracy of 77.5%. Application of this classifier to an Independent Cohort of additional stage I and II lung adenocarcinoma samples from another institution blinded for DFS/OS comparisons (N=21 DFS/OS &gt;47 months and N=4 DFS/OS &lt;23 months) is ongoing. Conclusion: We have validated miRNAs prognostic for DFS and OS in stage I and II lung adenocarcinoma in at least one cohort of 89 patients so far. A two miRNA classifier is currently being evaluated and we anticipate results for accuracy prediction on the Independent cohort at the time of the meeting.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4148. doi:1538-7445.AM2012-4148