For these 17 patients with paired biopsies, the median HER2 IHC and H scores prior to any treatment were 2+ and 100, while these were 3+ and 240 for the post EGFR TKI tumour samples, respectively, suggesting that EGFR TKI treatment either induced or increased HER2 expression (Fig. S1). The gene discussed is ERBB2; the disease is neoplasm.