To explore the effect of PAK4 on CDDP resistance in gastric cancer cells, we first established two CDDP-resistant gastric cancer cell lines-AGS/CDDP and MKN-45/CDDP by continuous exposure to CDDP starting at 0.1 μg/ml and increasing in a stepwise manner to 1 μg/ml. Here, PAK4 is linked to gastric cancer.