Effect of LY6K on proliferation of A549 cells. A, Effect of LY6K knockdown on proliferative activity of A549 cells, * p <0.05; B, Effect of LY6K knockdown on A549 cell cloning, ** p <0.01; C, Effects of LY6K knockdown on CyclinD1 and CDK4 in A549 cells, * p <0.05.