SMAD4 proficient PDAC cells were more likely to respond to TGF-β1 inhibitor treatment, but SMAD4 deficient PDAC cells were more sensitive towards EGFR inhibitor treatment to block cell migration in vitro. AsPC-1 and PANC-1 SMAD4 deficient and proficient cells were treated with TGF-β1 inhibitor SB231542 (0.5 μM) or EGFR inhibitor gefitinib (0.5 μM) and subjected to in vitro wound-healing assay. Each monolayer was scratched and incubated for overnight. The closure rate was photographed to compare their migratory ability between SMAD4 deficient and proficient PDAC cells with or without TGF-β1 or EGFR inhibitors treatment. Images are representative of three independent experiments (magnification 40×). P < 0.05.