Fig. 3.

Tumors in Vil-Cre;Nf2^lox/lox kidneys are foci of activated EGFR signaling. (A) Immunofluorescent detection using the pY100 antibody (green) revealed a marked increase in phosphotyrosine signaling in early (Right) and late (Middle) lesions in Vil-Cre;Nf2^lox/lox kidneys. Renal epithelial cells are displayed in red. (B) Immunoblot demonstrated activation of EGFR, its preferred dimerization partner ErbB2, and its downstream effectors in renal cortex lysates from 3- and 6-month-old Vil-Cre;Nf2^lox/lox mice. (C) Immunohistochemical detection of phosphorylated Akt, MAPK, and STAT-3 in paraffin sections of 3-month-old kidneys demonstrated that hyperactivation of these EGFR effectors was confined to neoplastic lesions in Vil-Cre;Nf2^lox/lox mice. The sections shown are representative of multiple mice, sections and lesions as defined in the legend to Fig. 1.