Genetically, FISH analysis showed focal EGFR amplification in the newly diagnosed tumour MGG70, which was retained at a higher level in the recurrent MGG70R specimen (Fig. 3), suggesting that the treatment with radiotherapy and temozolomide did not preferentially target cell populations harboring amplified EGFR. In contrast, all tumour cells had diploid EGFR signals in the post-dacomitinib MGG70RR (Fig. 3). Here, EGFR is linked to neoplasm.