Clinical significance of the loss of KiSS-1 and orphan G-protein-coupled receptor (hOT7T175) gene expression in esophageal squamous cell carcinoma.

Abstract

Lymph node metastasis is the most important predictor of prognosis in esophageal squamous cell carcinoma (ESCC). Recently, KiSS-1 was cloned as a human metastasis suppressor gene, and an orphan G-protein-coupled receptor (hOT7T175) was identified as the endogenous receptor of the KiSS-1 product. However, the clinical importance of KiSS-1 and hOT7T175 gene expression in ESCC remains unclear. In this study, total RNA was extracted from tumors and noncancerous epithelia of 71 patients with ESCC who underwent surgical esophageal resection. The expression levels of KiSS-1, hOT7T175, and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNAs were analyzed quantitatively by real-time reverse transcription-PCR and compared with the clinical findings. The mean KiSS-1:GAPDH and hOT7T175:GAPDH ratios of the tumors were 1.2 and 0.3 and were at the same levels as those in the noncancerous epithelia. The loss of KiSS-1 and hOT7T175 gene expression was detected in 38% and 61% of tumors. Loss of KiSS-1 and/or hOT7T175 gene expression was not correlated with tumor size or degree of tumor invasion but was found to be a significant predictor of lymph node metastasis. Loss of KiSS-1 or hOT7T175 gene expression may be an important biomarker for detection of lymph node metastasis in ESCC.