NKD1 and lung cancer: In order to explore how NKD1 knockdown increases the invasive ability of lung cancer cells, we measured the protein expressions of Dvl-1, Dvl-3 and β-catenin, the key protein factors involved in the Wnt pathway, as well as the transcriptional expression of MMP-7, the down-stream gene of Wnt pathway [16-18], in NKD1 down-regulated cells.