Our results clearly showed that only SLC15A2 and SLC15A4 could be used as clinical outcome prediction biomarkers for overall survival rate in lung adenocarcinoma with HR = 0.57 (0.45–0.72); log rank P-value = 2.5e-06 and HR = 0.4 (0.38–0.62); log rank P-value = 8.7e-09, respectively. This evidence concerns the gene SLC15A4 and lung adenocarcinoma.