The histological review identified LU2E as an SCLC sample, showing positive staining for chromogranin A, synaptophysin, and CD56, but negative for NapsinA, whereas LU2D was identified as an acinar predominant adenocarcinoma, with negative staining for chromogranin A and synaptophysin (Figure 4C). Here, SYP is linked to small cell lung carcinoma.