In a recent study, gene expression analysis of global transcriptome data was used to identify a candidate IHC marker for Merkel cell carcinoma and small cell lung cancer (SCLC), the result showed that CEACAM6 is promising as a differentiator between two neuroendocrine tumor, and the combination of CEACAM6 and thyroid transcription factor can improve the sensitivity and specificity of SCLC detection [19]. Here, CEACAM6 is linked to small cell lung carcinoma.