EGFR and metastatic neoplasm: HS values of sensitizing EGFR and T790M mutations between the unpaired primary and metastatic tumors were examined in cohort 2, and no significant differences in sensitizing EGFR (primary tumors: median 1.70, IQR 1.10–2.32, n = 53; metastatic tumors: median 1.47, IQR 0.77–1.98, n = 52; P = 0.121; Fig. 4F) and T790M HS values (primary tumors: median 0.59, IQR 0.36–0.99, n = 26; metastatic tumors: median 0.82, IQR 0.38–1.09, n = 26; P = 0.253; Fig. 4G) between the unpaired primary and metastatic tumors were observed.