Immunohistochemical study of secretogranin II in 62 neuroendocrine tumours of the digestive tract and of the pancreas in comparison with other granins.

An immunohistochemical study on 62 cases of gastrointestinal and pancreatic neuroendocrine tumours was performed in order to test the interest and specificity of a new anti-human secretogranin II antibody and compared to the other granin markers (chromogranin A and chromogranin B). Specific immunoglobulins were purified by affinity chromatography from an antiserum raised against a recombinant secretogranin II. Gastric tumours did not express secretogranin II, and ileal and appendiceal tumours only rarely expressed it (1/10 and 1/7 respectively), unlike the other classic neuroendocrine members of the granin family. In duodenal and pancreatic tumours, secretogranin II was detected when the other granins were also expressed. On the other hand, all rectal tumours expressed secretogranin II (7/7), frequently in the absence of chromogranin A. Though the granins expressed in tumoral tissue and in adjoining non tumoral tissue are mostly related, strong secretogranin II positivity occurred in 4 tumours while mucosa was secretogranin II negative. These observations highlight the interest for associating another antigranin such as secretogranin II to the classical markers of neuroendocrine tumours.