Transwell invasion experiments showed that the numbers of cells that moved to the lower chamber in the NC+NC group, KD+NC group, and KD+OE group were 113 ± 3.56, 30 ± 5.41, and 106 ± 3.46, respectively, indicating that the invasion of DDX39-knockdown melanoma cells can be activated by SNAIL overexpression (P < 0.001). The gene discussed is SNAI1; the disease is melanoma.