KiSS-1 has been identified as a putative metastasis-suppressor gene in human melanomas and breast cancer cell lines. Although loss of KiSS-1 expression has been associated with progression and poor prognosis of various cancers, the exact role of KiSS-1 expression in HCC is not well-defined. Our study investigated KiSS-1 expression levels in HCC and its role in invasion and metastasis of human HCC. The expression levels of KiSS-1 and MMP-9 protein were determined by tissue microarray (TMA) serial sections, immunohistochemistry and semi-quantitative image analysis. All clinical and histological data obtained were subjected to statistical analysis. The expression of KiSS-1 protein in HCC and intrahepatic metastasis lesions was significantly lower (P < 0.01) when compared with non-tumor liver tissue and normal liver tissue. Multivariate analysis revealed a significant inverse correlation between KiSS-1 expression and o1 TNM stage, (F = 7.113, P < 0.01) and o2 intrahepatic metastasis (t = 2.898, P < 0.01). Loss of KiSS-1 in intrahepatic metastasis versus primary carcinomas was statistically significant (P<0.01). We also found a negative correlation between KiSS-1 and MMP-9 expression in HCC (r = -0.506, P < 0.01). We conclude that loss of KiSS-1 during HCC metastasis, along with a concomitant upregulation of MMP-9 suggests a possible mechanism for cell motility and invasion during HCC metastasis, with KiSS-1 emerging as a possible therapeutic target during HCC metastasis.
(c) 2009 Wiley-Liss, Inc.