Up-regulation of the Receptor for Advanced Glycation End Product (RAGE) in Esophageal Cancer and Down-regulation in Lung Cancer and Their Relationship to Clinicopathological Features

Abstract

Objective: Esophageal and lung cancers are common thoracic malignant tumors. Although the receptor for advanced glycation end product (RAGE), a newly found tumor invasion gene, has been implicated in several human cancers, the relationship between expression of RAGE and clinical features of esophageal cancer remains unknown. Moreover, no data is available for comparison between RAGE expression in common thoracic tumors and their normal tissues. The aim of the present study is to investigate RAGE expression in esophageal and lung cancers and their relationship to clinicopathological features. Methods: We quantified RAGE mRNA and protein expression levels from 12 fresh esophageal cancer and 12 lung cancer tissues by real-time fluorescence quantitative polymerase chain reaction (RTFQ-PCR) and Western blotting, respectively. In addition, the relationship of RAGE expression and clinicopathological features was further determined by immunohistochemistry in 29 esophageal and 32 lung cancer patients. Results: RAGE mRNA expression was increased in esophageal cancer and decreased in lung cancer compared with normal tissues. Consistent with the expression in mRNA, RAGE protein expression in esophageal cancer and lung cancer also showed the difference in tumors and normal tissues. By immunohistochemistry, cells showed membranous and cytoplastic expression for RAGE. Higher RAGE expression was more frequently detected in infiltrating than noninfiltrating esophageal tumors. Lower RAGE expression in lung cancer tissues was associated with age and UICC stages, but not with tumor differentiation, histological typing, and lymph node metastasis. Conclusions: Expression of RAGE and relationships with their clinicopathological features were different in the thoracic tumors. RAGE was increased in esophageal cancer, especially in infiltrating tumors, but decreased and was closely associated with age and UICC stages in lung cancers. These results suggest that RAGE might be involved in the development of esophageal and lung cancers.