With the development of silica-induced pulmonary fibrosis, Han et al. found that the expression of miR-449a was decreased, which could negatively regulate the target gene B-cell lymphoma-2 (Bcl-2), trigger autophagy and inhibit the proliferation of fibroblasts, therefore playing a role in inhibiting pulmonary fibrosis [43]. The gene discussed is BCL2; the disease is pulmonary fibrosis.