To investigate the potential effects of endocytosis in the intrinsic resistance to TKIs displayed by ~80% of NSCLC patients with tumours driven by wtEGFR overexpression, Jo et al. used wide-field immunofluorescence microscopy to compare the endocytic trafficking of a fluorescent derivative of EGF bound to wtEGFR in NSCLC-derived gefitinib-sensitive H358 cells and gefitinib-resistant H1703 cells [40]. The gene discussed is EGF; the disease is non-small cell lung carcinoma.