(a) Radiographic images (computed tomography (CT) scans – Chest) and sites of tissue acquisition (tumor site indicated by red arrow) from EGFR-mutant lung cancer patient at the time initial presentation, followed by surgical resection of EGFR-mutant lung adenocarcinoma (right lung upper lobectomy, R1), at the time of development of metastatic disease (mediastinal lymph node metastasis, R2), upon progression to first line treatment with erlotinib (left lung metastases core needle biopsy, R3), and at autopsy after treatment with the 2nd line EGFR TKI rociletinib followed by PD and death (left lung metastasis, R4; right rib metastasis, R5; right lung metastasis, R6; spine metastasis, R7). Treatment immediately prior to imaging is indicated. Clinician assessment of radiographic response is indicated (PR – Partial Response, SD – Stable Disease, PD – Progressive Disease). Clinical histopathological diagnosis is indicated (LUAD = lung adenocarcinoma). Scale bar = 5 cm. (b) Representative images of hematoxylin and eosin (H&E) stained histopathological specimens obtained from surgery, biopsy, or autopsy as described in (a). Clinical histopathological assessment of all specimens revealed LUAD with no evidence of small cell lung cancer transformation. Scale bar = 50 microns.