Affected members may develop both gastric NETs and gastric neuroendocrine carcinomas (NECs) that show immune-reactivity for the neuroendocrine markers chromogranin A (CgA) and synaptophysin, as well as for the ECL-specific markers, vesicular monoamine transporter (VMAT2), and histidine decarboxylase (HDC) [24]. Here, HDC is linked to gastric neuroendocrine tumor, well differentiated, low or intermediate grade.