EGFR and neoplasm: EGFR mutation status concordance was found to be 88 % (89/101) via direct sequencing, with 11 discordant cases EGFR mutation-positive in the primary tumour only and one discordant case EGFR mutation-positive in the metastatic tumour only; however, retesting with a more sensitive heteroduplex analysis decreased the concordance to 83 % (84/101).