EGFR and neoplasm: Loss of EGFR amplification in the post-dacomitinib tumour indicates differential efficacy of EGFR-targeting within a single tumour depending upon EGFR amplification status28; it appears that EGFR-amplified cells were selectively eliminated by irreversible EGFR inhibition with dacomitinib and the non-amplified cells that survived seeded the re-recurrent tumour.