Immunohistochemical (IHC) staining test results showed that the tumor cells were positive for pancytokeratin (AE1/AE3) (Figure 2C), cytokeratin 7 (CK-7) (Figure 2D), thyroid transcription factor 1 (TTF-1) (Figure 2E) and carcinoembryonic antigen (CEA) (Figure 2F). The gene discussed is KRT7; the disease is neoplasm.