Tumour response to kinase inhibitor therapy can be observed in biopsied tissue.

<p>Tumour-bearing animals underwent surgical biopsy (pre-treatment) followed by a period of recovery before each was treated with 30mg/kg dacomitinib to inhibit EGFR. After 2 hours, a second biopsy was performed (post-treatment). Immunohistochemical detection of phosphorylated EGFR (Y1068, brown) in cryosections of biopsied tumours demonstrates that EGFR phosphorylation was significantly reduced after treatment with dacomitinib (lower row).Four representative mice are shown (#735, #736, #765 and #768). Sections were counterstained with haematoxylin (blue). Scale bar represents 100μm.