MicroRNA (miRNA) expression profiles for lung cancers were examined to investigate the miRNA involvement in lung carcinogenesis. miRNA microarray analysis identified statistical unique profiles, which could discriminate lung cancers from noncancerous lung tissues as well as molecular signature that differ in tumor histology. In addition, miRNA expression profiles correlated with survival of lung adenocarcinoma patients. High hsa-mir-155 and low hsa-let-7a-2 expression correlated with poor survival by univariate analysis (p=0.006 and p=0.033, respectively; log-rank test) as well as multivariate analysis for hsa-mir-155 (p =0.027; risk ratio 3.03; 95% confidence interval, 1.13-8.14) in lung adenocarcinoma patients. The miRNA expression signature on patient outcome was confirmed by real-time RT-PCR analysis of precursor miRNAs and cross-validated with an independent set of adenocarcinomas. These results indicate that miRNA expression profiles are a new class of diagnostic and prognostic markers of lung cancer

[Proc Amer Assoc Cancer Res, Volume 47, 2006]