Correlation between the expressions of leptin and its receptors (ObR, sObR) in gastric cancer

Objective: The expressions of leptin and its receptor (ObR) have been observed in human gastric cancer (GC) tissue. Leptin can promote the proliferation of GC cells. However, the correlation between leptin and ObR expressions in GC and the role of gastric ObR protein levels in patients with GC is still unclear. This study aimed to evaluate the relationship between leptin, gastric ObR protein and soluble leptin receptor (sObR) levels and whether their possible role of indicator in GC. Methods: Serum leptin, gastric leptin and serum sObR concentrations were determined in 30 male patients with GC and 25 male dyspeptic subjects by enzyme linked immunosorbent assay. We analysed the expression of gastric ObR levels in endoscopically obtained biopsy samples by using Western Blotting method. Results: Compared with controls, patients had lower serum leptin and higher gastric tissue leptin levels. sObR protein concentrations of patients were detected significantly higher, gastric ObR protein expression were lower than subjects in control group. Conclusion: Leptin in gastric cancerous region and sObR in circulation are overexpressed in GC. Their expressions are associated with malignancy. Decreased leptin levels, induces the sObR signal in circulation. This negative feedback regulation is also seen in gastric tissue: increased gastric tissue leptin levels inhibits gastric ObR protein expression. Thus, leptin and ObR may be important indicators in GC.