The positivity of CD56 in SCLC CTCs was obtained using the research mode of the CellSearch Analyzer II and the results showed that in all blood samples that contained CTCs there were CD56 positive cells, consistent with the CD56 staining profiles from matched tumor biopsies and confirming the dual epithelial and neuroendocrine phenotype and neoplastic origin of CTCs [11]. The gene discussed is NCAM1; the disease is small cell lung carcinoma.