The metastasis of lung cancer can spread to the lymph nodes around the lungs. Metastasis, rather than the primary cancer, judges patients survival. Wherefore, a more detailed study on transcriptome of metastatic lung adenocarcinoma including primary carcinoma was carried out. LUAD RNA-seq data and the corresponding clinical information were available from The Cancer Genome Atlas (TCGA), which included 522 cases but only 515 cases have transcriptome data. Differential expression analyses between cases and controls, between primary cancer and metastasis subgroup, or between TNM stages, were respectively carried out using edgeR package. Then, the Kruskal-Wallis tests were used to verify the gradient changes of cancer metastasis or staging with the differential expression genes. The survival analyses were calculated using the Kaplan-Meier algorithm and log-rank test. The functional predictions for the differentially expressed genes were porformed with the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (GO/KEGG). Single gene set enrichment analysis (single GSEA) was run to explore the biological pathways associated with the expressions of RN7SL494P gene based on the Molecular Signatures Database (MSigDB). 406 and 439 differentially expressed genes were identified respectively in lymph node metastasis or TNM stages. 112/296 intersection genes were associated with nodal metastasis and/or staging, among them only 25 genes were associated with the nodal metastasis, 13 genes were associated with the staging with gradient changes. Only one gene (RN7SL494P) was found to be associated with prognosis. But RN7SL494P was not found joining any biological functions or processes or cellular components with GO/KEGG analyses. Finally, single GSEA enrichment and pathway analyses showed that RN7SL494P might be involving in cancer development process and poor outcome in lung adenocarcinoma. These findings highlight the potential applications of RN7SL494P as a promising molecular predictor not only in nodal metastasis but prognosis evalution in lung adenocarcinoma patients.