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

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Abstract
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), pConclusions: 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.