Immunohistochemical and quantitative mRNA assessment of ghrelin expression in gastric and oesophageal adenocarcinoma

Background: Ghrelin is an orexigenic gut peptide produced predominantly by the stomach. Gastric mucosal ghrelin production could be compromised by an infiltrating adenocarcinoma. Aims: To assess the expression of ghrelin mRNA and peptide in oesophagogastric adenocarcinomas and adjacent non- neoplastic mucosa. Methods: 10 gastric and 22 oesophageal adenocarcinoma archival samples were randomly selected from a database. The presence of ghrelin- positive cells was assessed in cancer and corresponding non- neoplastic mucosa by immunohistochemistry. Quantitative reverse transcriptase polymerase chain reaction ( PCR) for ghrelin mRNA was also performed on 24 gastric and 8 oesophageal adenocarcinoma specimens and adjacent non- neoplastic mucosa. Results: Immunohistochemistry and reverse transcriptase PCR confirm a negligible expression of ghrelin in adenocarcinoma specimens. By contrast, non- neoplastic gastric mucosa was rich in ghrelin- positive cells and ghrelin mRNA. The number ( median and range) of ghrelin- positive cells per 2 mm section of non- neoplastic mucosa was 73 ( 45 - 215) in the corpus; this was significantly higher than in cardia mucosa ( 9 ( 0 - 64), p, 0.001) and antral mucosa ( 5 ( 0 - 14), p, 0.001). Conclusions: Gastric and oesophageal adenocarcinomas have no ghrelin- producing cells. The highest level of ghrelin expression was noted in the non- neoplastic mucosa of the gastric corpus. Disruption of the gastric ghrelin- producing mechanism may occur during oesophagogastric malignancy