Western blot image of human A431 cells untreated (lanes 1 & 3) or treated with EGF (100 ng/ml) for 5 min. The blot was probed with anti-EGFR (Tyr-1101) monoclonal antibody (lanes 1 & 2) or anti-EGFR (Cytoplasmic) monoclonal antibody (lanes 3 & 4).