[European Journal of Histochemistry 2013; 57:e30] [page 199]

As a metastasis suppressor, KiSS1 has been implicated in numerous human cancers. However, recent studies have demonstrated that KiSS1 promotes tumor growth and metas-tasis in breast cancer, and it is unclear about the expression and function of KiSS1 in human osteosarcoma (OS). The aim of the present study was to investigate the role and molecular mechanisms of KiSS1 in human OS. The expression of KiSS1 was assessed by immunohistochemical assay using a tissue microarray procedure in forty cases of OS tis-sues. A gain-of-function approach was used to observe the effects of lentiviral vector-mediat-ed overexpression of KiSS1 (Lv-KiSS1) on the biological behaviors including proliferative activities and invasive potential of OS MG-63 cells, indicated by MTT and Transwell assays, respectively. The results showed that the expression of KiSS1 protein in OS tissues was significantly lowered compared to that in adja-cent non-cancerous tissues (42.5 % vs 70.0%, P=0.023), and had negative correlation with distant metastases of the tumor (P=0.019). Overexpression of KiSS1 inhibited prolifera-tion and invasion of OS cells with the decreased expression of p38 MAPK and matrix metalloproteinase-9 (MMP-9). Taken together, our findings indicate that the decreased expression of KiSS1 is correlated with distant metastasis of OS, and KiSS1 may function as a tumor suppressor in OS cells through inhibi-tion of the MAPK pathway, suggesting that KiSS1 may serve as a potential therapeutic tar-get for the treatment of cancer