Serum CgA levels were reportedly elevated in 100% of gastrinomas, 89% of pheochromocytomas, 80% of small intestinal carcinoids, 69% of non-functioning pancreatic NETs (Pan-NETs), and 50% of MTCs, in which tumor growth paralleled to serum CgA levels [42-44]. Here, CGA is linked to gastrin-producing neuroendocrine tumor.