Fig. 2

EGFR and HER-2 protein and mRNA expression levels in EC cell lines. a Cells were cultured, harvested, solubilized in detergent, and resolved by 12 % reducing SDS-PAGE. Each sample was confirmed with anti-EGFR, anti-HER-2, and anti-β-actin antibody. The detection of β-actin protein served as a loading control. The blot is representative of three independent experiments. *, increased expression levels of EGFR protein in HEC-1A compared to those in HEC293 and Ishikawa, P < 0.001 **, increased expression levels of EGFR protein in HEC-1A compared to those in KLE, and increased expression levels of HER-2 protein in Ishikawa and KLE compared to those in HEC-1A, P < 0.05. b EGFR and HER-2 mRNA levels were measured by quantitative RT-PCR. Data were normalized with GAPDH mRNA levels in each sample. Data represent the means ± SEMs of five independent experiments. *, increased expression levels of EGFR mRNA in HEC-1A compared to those in HEC293 and Ishikawa, P < 0.005 **, increased expression level of EGFR mRNA in HEC-1A compared to those in KLE, and increased expression level of HER-2 mRNA in Ishikawa and KLE compared to those in HEC-1A, P < 0.05