title: Adiponectin receptor 2 is negatively associated with lymph node metastasis of colorectal cancer.
abstract: Adiponectin is a hormone secreted by adipose tissue and has a variety of functions including the inhibition of tumor growth. The expression and function of the two major adiponectin receptors, AdipoR1 and AdipoR2, in malignant tissue have not been well characterized. In the present study, we evaluated the mRNA levels of AdipoR1 and AdipoR2 expression in 48 surgically resected colorectal cancer specimens, as well as normal colonic mucosa, by quantitative RT-PCR. The values obtained were standardized by β-actin mRNA, and the correlation between their relative expression levels and the clinicopathological characteristics of the patients was examined. The relative expression levels of AdipoR1 and AdipoR2 were significantly reduced in cancer tissue compared with normal tissue (AdipoR1: 0.97±0.39 vs. 1.37±0.41, P<0.0001; AdipoR2: 0.92±0.31 vs. 1.60±0.46, P<0.0001). AdipoR1 and AdipoR2 levels were further reduced in tumors with nodal metastases and the difference was statistically significant in the case of AdipoR2 (0.79±0.27 vs. 1.02±0.30, P=0.012). The results of this study demonstrated that the expression levels of adiponectin receptors are reduced in cancer specimens compared to normal tissue, indicating a downregulation in the course of the development and progression of colorectal cancer. Since adiponectin is abundantly present in the whole body and has inhibitory effects on cancer cells, this downregulation of the receptors may be an escape mechanism of malignant cells from the suppressive effects of adiponectin.
authors: Department of Surgical Oncology, Faculty of Medical Sciences, the University of Tokyo, Tokyo 113-8655, Japan.
authors: Masaya
authors: M
authors: Hiyoshi
authors: Nelson H
authors: NH
authors: Tsuno
authors: Kensuke
authors: K
authors: Otani
authors: Kazushige
authors: K
authors: Kawai
authors: Takeshi
authors: T
authors: Nishikawa
authors: Yasutaka
authors: Y
authors: Shuno
authors: Kazuhito
authors: K
authors: Sasaki
authors: Kumiko
authors: K
authors: Hongo
authors: Manabu
authors: M
authors: Kaneko
authors: Eiji
authors: E
authors: Sunami
authors: Koki
authors: K
authors: Takahashi
authors: Hirokazu
authors: H
authors: Nagawa
authors: Joji
authors: J
authors: Kitayama