These phenotypically similar, small cell neuroendocrine cancers (SCNCs) are classified as high-grade, poorly differentiated small cell carcinomas that commonly express neuroendocrine markers like chromogranin A (CHGA), neural cell adhesion molecule 1 (NCAM1), and synaptophysin (SYP) (4). This evidence concerns the gene NCAM1 and small cell carcinoma.