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World J Gastroenterol. Sep 14, 2006; 12(34): 5517-5522
Published online Sep 14, 2006. doi: 10.3748/wjg.v12.i34.5517
Expression pattern of leptin and leptin receptor (OB-R) in human gastric cancer
Makoto Ishikawa, Joji Kitayama, Hirokazu Nagawa
Makoto Ishikawa, Joji Kitayama, Hirokazu Nagawa, Department of Surgery, Division of Surgical Oncology, the University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
Correspondence to: Makoto Ishikawa, Department of Surgical Oncology, Faculty of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. makoto-ishi@umin.ac.jp
Telephone: +81-3-38155411-33246 Fax: +81-3-38116822
Received: July 29, 2005
Revised: August 8, 2005
Accepted: August 26, 2005
Published online: September 14, 2006
Abstract

AIM: To examine the expression of leptin and its receptor, OB-R, in normal gastric mucosa and neoplasia.

METHODS: By immunohistochemical staining using specific 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 carcinoma 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 significant correlation with the level of leptin expression. The expression levels of both leptin and OB-R tended 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 invasion 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%) patients. In contrast, none of the carcinomas that lacked expression of leptin and OB-R showed hematogenous metastasis.

CONCLUSION: Overexpression of leptin and expression 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.

Keywords: Leptin; OB-R; Gastric cancer