Immunohistochemistry markers for non-neuroendocrine components depend on the histologic subtype, with adenocarcinomas expressing cytokeratin 19, cytokeratin 7, carcinoembryonic antigen, and CA 19-9.3 However, diagnosis of a MiNEN by immunohistochemistry-based quantification alone is insufficient because neuroendocrine markers may be present in non-neuroendocrine tumors, and discrete histopathologic findings of each morphology must be present. This evidence concerns the gene CEACAM5 and neuroendocrine neoplasm.