EGFR mRNA expression in livers from wt, Cα and Cβ KO mice. The level of EGFR cDNA was determined by real time RT-PCR. The levels of EGFR mRNA expression in Cα KO versus wt livers (a) and Cβ KO versus wt livers (b) were calculated as relative copy numbers normalized against GAPDH mRNA. Relative EGFR mRNA expression was calculated using the formula (E/G) × 100, where E and G are the relative copy numbers of EGFR and GAPDH mRNA, respectively. The results are given as +/- SEM where n = 3.