Estudo das células imunorreativas à ghrelina eprepro-ghrelina na hiperplasia endócrina associada à gastrite atrófica do corpo e em tumores neuroendócrinos tipo I do estômago

Abstract

Introduction: Ghrelin is a 28 amino acid peptide secreted mainly by endocrine cells presentin the gastric mucosa and acknowledged as an endogenous releaser of growth hormone. Theimmunohistochemical expression of ghrelin has been described in neuroendocrine tumors, and itis believed that may exert modulating action related to the growth of these tumors. Objective: Tostudy the presence of ghrelin and preproghrelin immunoreactive cells in gastric neuroendocrinetumors associated with atrophic body gastritis. Methods: Endoscopic biopsies from 15 patients withneuroendocrine tumor of the gastric mucosa associated with atrophic body gastritis were performedfor immunohistochemistry, and specific chromogranin, ghrelin and preproghrelin antibodies wereapplied. The immunohistochemical expression was assessed in tumor cells and endocrine micronodularhyperplasia present in mucosa adjacent to the tumor, and it was classified in relation to the number ofstained cells. Results: Chromogranin was positive in 14 out of 15 tumors. Ghrelin and preproghrelinimmunoreactive cells were detected in 11 (73%) and 13 (87%) tumors, respectively. There was asignificant correlation between the immunohistochemical results of both antigen expressions (kappa =81%). Ghrelin and preproghrelin expression was detected in hyperplastic nodules present in the mucosaadjacent to the tumor in seven and eight cases, respectively. There was no correlation between theseresults and those observed in neoplastic cells. Conclusion: Ghrelin and preproghrelin immunoreactivecells may be found in variable number in Type I neuroendocrine gastric tumors and in hyperplasticnodules associated with these tumors. However, it remains unclear what role these peptides play onthe development of these tumors.