Some of non-insulinoma PNETs with relatively small size still had very high serum levels of CgA, for example, CgA level was 4572 ng/ml in a gastrinoma of 1.5 cm in size, and the highest CgA level in present study was more than 9000 ng/ml in a glucagonoma of 2.5 cm in size. This evidence concerns the gene CGA and gastrin-producing neuroendocrine tumor.