Untreated (–) and treated (+) A431 whole cell extracts (30 μg) were separated by 5% SDS-PAGE, and the membrane was blotted with EGFR (phospho Thr669) antibody (GTX133596) diluted at 1:2000. The HRP-conjugated anti-rabbit IgG antibody (GTX213110-01) was used to detect the primary antibody.