Ghrelin, an orexigenic
hormone, is a
peptide that binds to the
growth hormone secretagogue receptor; it is secreted mainly by enteroendocrine cells in the oxyntic glands of the stomach.
Ghrelin serves a role in both local and systemic physiological processes, and is implicated in various pathologies, including
neoplasia, with tissue expression in several types of
malignancies in both in vitro and in vivo studies. However, the precise implications of the
ghrelin axis in
metastasis, invasion and
cancer progression regulation has yet to be established. In the case of gastrointestinal (GI) tract
malignancies,
ghrelin has shown potential to become a prognostic factor or even a therapeutic target, although data in the literature are inconsistent and unsystematic, with reports untailored to a specific histological subtype of
cancer or a particular localization. The evaluation of immunohistochemical expression shows a limited outlook owing to the low number of cases analyzed, and in vivo analyses have conflicting data regarding differences in
ghrelin serum levels in patients with
cancer. The aim of this review was to examine the relationship between
ghrelin and GI tract
malignancies to demonstrate the inconsistencies in current results and to highlight its clinical significance in the outcome of these patients.