To investigate if the observed heterogeneity in EGFR expression extends to cultured cell lines, we analyzed six cell lines derived from EGFR-mutant NSCLC patients, including three commercially available (PC-9, H1975, HCC4006) and three patient-tumor derived lines (DFCI-284, DFCI-243, DFCI-169) (Table 1). Here, EGFR is linked to neoplasm.