Figure 1

Patterns of EGFR expression. a) Case with an extent positivity ≥25% with strong membrane staining of tumor cells. Insert and arrow: note the membranous positivity pattern (immunoperoxydase × 100 and × 400). b) Case with an extent positivity <25% with weak membrane staining of some tumor cells (arrow) (immunoperoxydase × 400). c) Case with negative staining (immunoperoxydase × 200).