Downregulation of KiSS-1 expression is responsible for tumor invasion and worse prognosis in gastric carcinoma.

KiSS-1 is a promising candidate tumor-suppressor gene and may play a key role in the metastatic cascade. The expression profile and the role of KiSS-1 in cancer progression are largely unknown in most of the cancers, including gastric cancer. In this study, KiSS-1 expression was evaluated by RNase protection assay and localization was done by in situ hybridization in 40 gastric cancers and their adjacent normal gastric mucosa. For comparison with clinicopathologic characteristics and patient prognosis, all patients were divided into 2 groups having high and low KiSS-1 expression by using the median as the cutoff value of KiSS-1 expression as determined by the RNase protection assay. Gastric cancers with low KiSS-1 had frequent venous invasion, distant metastasis and tumor recurrence. Accordingly, patients with low KiSS-1-expressing tumors had a significantly worse overall and disease-free survival. In multivariate analysis, KiSS-1 became the strongest independent prognostic factor among the conventional prognosticators for gastric cancer patients. Collectively, these findings suggest that KiSS-1 may play a crucial role in gastric cancer invasion and could be a useful target for therapeutic intervention.