Adiponectin receptor expression in gastric carcinoma: implications in tumor development and progression

Adiponectin, an adipocyte-secreted endogenous insulin sensitizer, appears to play an important role in progression of several malignancies. Expression of adiponectin receptors--AdipoR1 and AdipoR2--has been documented in gastric cancer (GC) cell lines, but its role in GCs is still controversial. We investigated expression level of 2 adiponectin receptors and correlated their expression with prognosis in GC patients.

We immunohistochemically evaluated AdipoR1 and AdipoR2 expression in 59 non-neoplastic gastric mucosas, 48 gastric adenomas, 250 GCs, and 58 lymph nodes involved by metastatic GC and assessed its association with clinicopathologic characteristics.

Expression rates of both receptors increased stepwise in non-neoplastic gastric mucosa, gastric adenoma, intestinal-type GC, and metastatic GC (p < 0.001). AdipoR1 and AdipoR2 expression was observed in 85 (34.0 %) and 118 (47.2 %) GC cases, respectively. Expression rates were higher in intestinal-type GC than in diffuse-type GC (p < 0.001 and 0.016, respectively). AdipoR1 and AdipoR2 expression was more frequent in advanced GC than in early GC (p < 0.001, each) and was associated with lymphatic invasion (p = 0.046 and 0.001, respectively). AdipoR2 expression was associated with poor overall and disease-free survival (p = 0.001 and 0.007, respectively). AdipoR1 expression was associated with poor disease-free survival for intestinal-type GC patients (p = 0.046). In multivariate analysis, AdipoR2 was an independent prognostic factor for intestinal-type GC (p = 0.017).

Adiponectin receptor expression is related to GC development and progression, especially intestinal-type GC. Thus, adiponectin receptor expression can serve as a prognostic marker in GC patients.