IMMUNOHISTOCHEMICAL STUDY OF SECRETOGRANIN-II IN 62 NEUROENDOCRINE TUMORS OF THE DIGESTIVE-TRACT AND OF THE PANCREAS IN COMPARISON WITH OTHER GRANINS

An immunohistochemical study on 62 cases of gastrointestinal and pancr eatic neuroendocrine tumours was performed in order to test the intere st and specificity of a new anti-human secretogranin II antibody and c ompared to the other granin markers (chromogranin A and chromogranin B ). Specific immunoglobulins were purified by affinity chromatography f rom an antiserum raised against a recombinant secretogranin II. Gastri c tumours did not express secretogranin II, and ileal and appendiceal tumours only rarely expressed it (1/10 and 1/7 respectively), unlike t he other classic neuroendocrine members of the granin family. In duode nal and pancreatic tumours, secretogranin II was detected when the oth er granins were also expressed. On the other hand, all rectal tumours expressed secretogranin II (7/7), frequently in the absence of chromog ranin A. Though the granins expressed in tumoral tissue and in adjoini ng non tumoral tissue are mostly related, strong secretogranin II posi tivity occurred in 4 tumours while mucosa was secretogranin II negativ e. These observations highlight the interest for associating another a nti-granin such as secretogranin II to the classical markers of neuroe ndocrine tumours.