Immunohistochemical staining:
For immunohistochemistry (IHC) staining, slices from the chosen paraffin blocks were cut into 4 micrometers thick sections. Primary anti-EGFR antibody (ABclonal® polyclonal, rabbit source, EGFR antibody, Cat. No. A11351) was produced and incubated on slides. After that, the secondary antibody of choice (ABclonal® anti rabbit IgG, Cat. No. Ab214880) was incubated. Prior to dehydration and mounting, all slides were lightly counterstained with hematoxylin for 30s.