In the current study, using urethane-induced lung cancer mouse model, we screened some lncRNAs expression in the serum exosomes of mice and then we further investigated the functions and potential mechanisms of the exosomal lncRNA growth arrest specific 5 (GAS5), which is relatively highly homologous in human and mouse, in human lung cancer cells and human umbilical vein endothelial cells (HUVECs). The gene discussed is GAS5; the disease is lung cancer.