Tumor cells showed diffuse immunopositivity for calcitonin, HMB-45, carcinoembryonic antigen, synaptophysin, chromogranin, vimentin and epithelial membrane antigen but focal paranuclear dot-like positivity for cytokeratin (Fig 2a–f), and were negative for thyroglobulin, S-100, melan-A and TTF (Table 2). The gene discussed is CEACAM5; the disease is neoplasm.