Feurle Gerhard E, Anlauf Martin, Hamscher Gerd, Arnold Rudolf, Klöppel Günter, Weihe Eberhard
DRK-Krankenhaus Neuwied, Philipps Universität Marburg, Germany.
Gastroenterology. 2002 Nov;123(5):1616-26. doi: 10.1053/gast.2002.36590.
BACKGROUND & AIMS: Xenin is a 25-amino acid peptide produced by specific endocrine cells of the duodenal mucosa. We investigated whether xenin is expressed in neuroendocrine tumors.
Seventy-two foregut and midgut neuroendocrine tumors were examined by means of immunohistochemistry, confocal laser microscopy with an antibody against the C-terminus of xenin, and high-pressure liquid chromatography after acidic extraction, assessed by radioimmunoassay.
We found xenin-immunoreactive cells in 23 of 26 duodenal neuroendocrine tumors, including gastrinomas, somatostatinomas, and nonfunctioning and enterochromaffin cell tumors. In these tumors, up to 20% of the endocrine cells were xenin immunoreactive, and xenin immunoreactivity was concentrated in secretory granules. Xenin was coexpressed with chromogranin A. We found no xenin expression in gastrin-, somatostatin-, and serotonin-immunoreactive cells. High-pressure liquid chromatography after acidic extraction revealed 497 +/- 285 pmol of xenin per gram of tissue in 5 duodenal gastrinomas. The other neuroendocrine tumors, such as bronchial carcinoids, gastric enterochromaffin-like cell carcinoids, gastric and ileal enterochromaffin cell carcinoids, insulinomas, and gastrinomas of pancreatic origin, did not contain immunoreactive xenin.
Xenin is a peptide marker specific to neuroendocrine tumors of the duodenum. This finding may be useful in tumor classification and in the differential diagnosis of neuroendocrine tumors of the upper gut.
胃泌素释放肽是一种由十二指肠黏膜特定内分泌细胞产生的含25个氨基酸的肽。我们研究了胃泌素释放肽在神经内分泌肿瘤中是否表达。
采用免疫组织化学、针对胃泌素释放肽C末端的抗体进行共聚焦激光显微镜检查以及酸性提取后用放射免疫分析法评估的高压液相色谱法，对72例前肠和中肠神经内分泌肿瘤进行检测。
我们在26例十二指肠神经内分泌肿瘤中的23例中发现了胃泌素释放肽免疫反应性细胞，包括胃泌素瘤、生长抑素瘤、无功能性肿瘤和肠嗜铬细胞肿瘤。在这些肿瘤中，高达20%的内分泌细胞呈胃泌素释放肽免疫反应性，且胃泌素释放肽免疫反应性集中在分泌颗粒中。胃泌素释放肽与嗜铬粒蛋白A共表达。我们在胃泌素、生长抑素和5-羟色胺免疫反应性细胞中未发现胃泌素释放肽表达。酸性提取后的高压液相色谱法显示，5例十二指肠胃泌素瘤每克组织中含有497±285皮摩尔的胃泌素释放肽。其他神经内分泌肿瘤，如支气管类癌、胃肠嗜铬样细胞类癌、胃和回肠肠嗜铬细胞类癌、胰岛素瘤以及胰腺来源的胃泌素瘤，均未含有免疫反应性胃泌素释放肽。
胃泌素释放肽是十二指肠神经内分泌肿瘤的一种特异性肽标志物。这一发现可能有助于肿瘤分类以及上消化道神经内分泌肿瘤的鉴别诊断。
