Fig. 1.

Localized somatic expression of EGFR in adult mouse brains form tumors. (A) Schematic representation of the activation of the conditional EGFR transgenes. A strong ubiquitous promoter (CAGGS) is positioned upstream of a transcriptional stop cassette (STOP) which is flanked by 2 loxP sites (blue triangles), followed by either wild-type (WT) or mutated (vIII) human EGFR cDNAs and a polyA signal sequence (purple rectangle). The expression of EGFR is conditional to the removal of the stop cassette, which is mediated by an adenovirus expressing Cre recombinase. (B) Tumor-free survival (Kaplan-Meier) analysis of Ad-Cre-injected conditional EGFR cohorts of mice with the indicated genotypes. EGFR^WT/WT, n = 6; EGFR^vIII/vIII, n = 5. For EGFR^WT/WT, EGFR^vIII/vIII, and EGFR^WT/vIII, all on an InkΔ2/3^−/− and PTEN^−/− background, n = 33, n = 4, and n = 8, respectively.