Developmental expression of EGFR, ERBB2, ERBB3, and Met in HS-EGFRKO and wild-type mice. We performed immunoblots and then analyzed by densitometry the relative expression of EGFR (A), ERBB2 (B), ERBB3 (C), and Met (D) in HS-EGFRKO and wild-type mice from 1 to 300 days of age. This figure shows decreased expression of EGFR even before weaning in the HS-EGFRKO mice. During early development there are statistically significant increases in ERBB2, ERBB3, and Met. No such increases are observed after weaning. *P < 0.05.