Purpose: KiSS-1 has been cloned as a human metastasis suppressor gene and an orphan G-protein-coupled receptor (hOT7T175) identified as the endogenous receptor of the KiSS-1 product. In the present study, we evaluated the clinical importance of KiSS-1 and hOT7T175 gene expression in hepatocellular carcinoma (HCC).
Methods: The expression levels of KiSS-1, hOT7T175 and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) messenger RNAs (mRNAs) were analyzed quantitatively by real-time reverse transcriptase polymerase chain reaction (RT-PCR) in 60 surgically resected HCCs. The KiSS-1/GAPDH and hOT7T175/GAPDH ratios of tumors were compared with clinicopathological findings.
Results: Loss of KiSS-1 mRNA expression was not detected in HCCs. The mean KiSS-1/GAPDH ratio did not change between non-cancerous cirrhotic livers and carcinomas. On the other hand, the average hOT7T175/GAPDH ratios increased from non-cancerous livers (0.08) to carcinomas (0.48). Overexpression of KiSS-1 and hOT7T175 genes was recognized in 6 tumors, which were in an advanced stage and showed poor survival.
Conclusion: Overexpression of KiSS-1 and hOT7T175 genes was frequently observed and correlated with HCC progression; thus, the possibility that overexpressed KiSS-1 and hOT7T175 peptides mediate growth signals into cancer cells in HCCs is suggested.