Effects of FBXO31 on cell proliferation and colony formation of lung cancer cells. A. MTT assay of A549 cells. Data represent the means ± SD. B. Colony formation assay of A549 cells. Left, images are representative of three independent experiments. Right, columns, mean of three separate experiments; bars, SD. **P < 0.01. C and D. Expression of FBXO31 in A549 cells. Columns, mean of three separate experiments; bars, SD. ***P < 0.001.