To identify specific circulating
microRNAs that were associated with the
lymphatic metastasis in
lung cancer, we performed
miRNA microarray analysis of lymph node with and without
metastasis from five
lung cancer patients. Top six differentially expressed
miRNAs were selected for further validation. A training cohort of 26 patients with
lung cancer was firstly recruited and the selected
miRNAs in the plasma samples were investigated. miRNA-422a, with highest diagnostic accuracy in
lymphatic metastasis was identified (AUC, area under the receiver operating characteristic curve, 0.744; 95%CI, 0.570-0.918). The diagnostic value of miR-422a was also demonstrated by a validation cohort of 51
lung cancer patients (AUC, 0.880; 95%CI, 0.787-0.972). Moreover, a high diagnostic value was also observed after integrated analysis of training and validation cohorts (AUC, 0.792; 95%CI, 0.688-0.896). The odds ratio of high miR-422a expression for
lymphatic metastasis in
lung cancer was 13.645 (95%CI, 2.677-69.553) after adjustment of the potential confounding factors. Furthermore, we predicted the target genes of miR-422a by combining the online database, miRcords, and the data from GEO and TCGA. Sixty-one target genes of miR-422a that might be involved in
lymphatic metastasis in
lung cancer were identified. And GO analysis suggested multiple target genes relatively concentrated in the biological processes of apoptosis, transport, and
protein phosphorylation.