Leptin expression in adenocarcinomas and adenomatous polyps in patients with colon cancer

Background : Though leptin, the adipocytes-derived hormone, plays an important role in obesity, it can act as a growth factor for several cancers including gastrointestinal malignancies. Based on this background, we investigated whether leptin expression correlated with the clinicopathological characteristics or disease outcome in patients with colon cancer. We immunohistochemically analyzed the expression of leptin in a “colon adenoma-carcinoma sequence” in the normal colon mucosa, an adenomatous polyp and adenocarcinoma tissue, from a surgical resection for each patient. Methods : We collected samples from 24 patients with a colorectal adenocarcinoma that was removed in either a total colectomy or hemicolectomy, and who presented with an adenomoatous polyp and an adenocarcinoma in the same surgical specimen. Leptin expression was assessed using immunohistochemical methods and was evaluated by grading the staining intensity as 0, +1, +2, +3. Results : Whereas leptin expression was observed in 4.2% (1/24) of the normal colon mucosa, adenomatous polyps and adenocarcinomas showed 33.3% (8/24) and 50.0% (12/24) expression of leptin, respectively (p