Overexpression of leucine‐rich repeat‐containing G protein‐coupled receptor 5 in gastric cancer

Gastric cancer is one of the most common malignancies worldwide and patients with advanced gastric cancer still have poor clinical outcomes. The overexpression of leucine‐rich repeat‐containing G protein‐coupled receptor 5 ( LGR 5) mRNA in colorectal cancer and its correlation with clinicopathological factors were recently reported by us. In this study, we show LGR 5 mRNA overexpression in human gastric cancer specimens by quantitative RT‐PCR and in situ hybridization and assess a correlation with clinicopathological factors. The mean expression of LGR 5 mRNA in cancerous tissues was five times higher than that in normal tissue ( P  = 0.0002). Furthermore, LGR 5 mRNA expression show marked variation among cases and significantly increased in cases where lymphatic invasion was present compared with those where it was absent ( P  = 0.0056). Although the mean expression level of LGR 5 was observed to be higher in nodal metastasis and venous invasion positive cases compared to negative cases, a significant difference was not observed. These results suggest that LGR 5 can be a biomarker for malignancy in gastric cancer.