The overexpression of BTG2 may inhibit the growth and proliferation through inhibiting the protein expression of cyclin D1, and invasiveness through inhibiting the protein expression of MMP-1 (matrix metalloproteinase-1) and MMP-2 (matrix metalloproteinase-2) in the A549 human lung cancer cell line [27,28]. The gene discussed is CCND1; the disease is lung carcinoma.