Expression of KiSS‐1 Gene and its Role in Invasion and Metastasis of Human Hepatocellular Carcinoma

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 ○1 TNM stage, (F = 7.113, P < 0.01) and ○2intrahepatic 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. Anat Rec, 292:1128–1134, 2009. © 2009 Wiley‐Liss, Inc.