Tissue specimens from 47 NETs were analyzed. Antibodies to CgA 250–284, CgB 244–255, SgII 172–186 (C-terminal secretoneurin) and SgIII 348–361 were used for immunostaining.
SgIII was expressed in 41 of 47 NETs. The expression of SgIII agreed well with that of CgA, CgB and SgII, with exceptions of phaeochromocytomas, where more CgB and SgII immunoreactive cells were observed and parathyroid adenomas, which were only stained by CgA. In rectal NETs more cells expressed SgIII than CgA.
This is the first report on SgIII expression in various NETs. A majority of tumours studied displayed SgIII immunostaining, which indicates a functional relationship with the other granins.