After 3 days of radiotherapy, pathological findings presented that lung lesions cells were distributed in flaky nest-like shape, arranged densely, with hyperchromatic nuclei, visible areas of focal necrosis, moreover, immunohistochemistry of lung lesions showed positive staining for thyroid transcription factor-1(TTF-1), cytokeratin-PAN (CK-Pan), synaptophysin (Syn), chromogranin A (CgA), CD56, P53 (90%) and Ki67 (70%), and negative staining for NapsinA and P40 in tumor cells (Fig. 4). The gene discussed is TTF1; the disease is neoplasm.