Expression pattern of leptin and leptin receptor （OB-R） in human gastric cancer

INTRODUCTION Previous studies have shown a positive association be- tween adiposity and increased risk of cancers of the endo- metrium, kidney, gallbladder (in women), breast (in post- menopausal women), and colon (particularly in men)[1-9]. Consistently,…

Expression pattern of leptin and leptin receptor (OB-R) in human gastric cancer

AIM: To examine the expression of leptin and its receptor, OB-R, in normal gastric mucosa and neoplasia. METHODS: By immunohistochemical staining using specifi c antibodies, we evaluated the expression of leptin and OB-R in 207 gastric carcinomas (100 early and 107 advanced carcinomas) and analyzed their relationship with clinicopathological features. RESULTS: Both normal gastric epithelium and carci- noma cells expressed a significant level of leptin. In cases with OB-R staining, carcinoma cells showed OB-R- positive expression, but the intensity was weaker than that in normal mucosa. The expression of OB-R showed a signifi cant correlation with the level of leptin expres- sion. The expression levels of both leptin and OB-R tend- ed to increase as the depth of tumor invasion or TMN stage increased (P < 0.01). Lymph node metastasis was detected in 49.5% (47/95) of leptin-strong cases and in 50.5% (48/95) of OB-R-positive cases, and the rate was 33% (37/112) in leptin-weak cases and 17% (19/112) in OB-R-negative cases. Both venous and lymphatic inva- sion also tended to be observed frequently in positive tumors as compared with negative tumors. Interestingly, in the 96 leptin- or OB-R-positive tumors, hematogenous metastasis was detected preoperatively in 3 (3.1%) pa- tients. In contrast, none of the carcinomas that lacked expression of leptin and OB-R showed hematogenous metastasis. CONCLUSION: Overexpression of leptin and expres- sion of OB-R may play a positive role in the process of progression in gastric cancer. Functional upregulation of leptin/OB-R may have a positive role in the development and initial phase of progression in gastric cancer.