The depletion of MEG8 significantly reduced the tumor growth of A549 cells in vivo, in which the inhibitor of miR-15a-5p and miR-15b-5p could rescue the phenotype, as demonstrated by the tumor volume (P < 0.05) (Fig. 7a), tumor weight (P < 0.05) (Fig. 7b), tumor size (Fig. 7c) and the expression of Ki-67 in the lung tissues of mice (Fig. 7d). The gene discussed is MKI67; the disease is neoplasm.