Currently there are few effective therapeutic options to reduce metastasis-related recurrence. microarray platform. In addition, survival prediction was successful in patients with early disease, such as small (<5 cm in diameter) and solitary tumors, and the signature predicted particularly well for early recurrence risk (<2 years), especially when combined with serum alpha fetoprotein or tumor staging. In conclusion, we have demonstrated in two independent cohorts with mixed LAMP3 etiologies and ethnicity that the metastasis gene signature is a useful tool to predict HCC outcome, suggesting the general utility of this classifier. We recommend the use of this classifier as a molecular diagnostic test to assess the risk that an HCC patient will develop tumor relaps within 2 years after surgical resection, particularly for those with early stage tumors and solitary presentation. Keywords:Early Recurrence, Prognosis, Gene Signature, HCC == INTRODUCTION == Hepatocellular carcinoma IV-23 (HCC) is the most frequent malignant tumor in the liver and the third leading cause of cancer-related deaths worldwide (1). HCC is most prevalent in developing countries, but its incidence is increasing in developed countries due to chronic infection with hepatitis C virus (HCV) and resulting liver cirrhosis(2). In the United States, liver cancer has the fastest growing cancer death rate, even though, the overall cancer mortality rate has declined during the past years (3). The poor outcome of HCC patients is mainly caused by the high IV-23 frequency of late-stage disease, metastasis and de novo tumor formation in the diseased liver, the so-called field effect (4,5). Currently, surgery is the most effective treatment, but the recurrence rate is high, mainly due to the dissemination of malignant cells (6). Although early-stage tumors can be treated by resection, liver transplantation or local ablation, few patients present with early-stage disease and many patients still suffer from recurrence after treatment of early-stage tumors (7). Metastasis contributes to 90% of all cancer related deaths, emphasizing the importance of metastasis risk prediction (8). Unlike other tumor types, HCC metastasis occurs mainly within the liver itself with new tumor colonies frequently invading into the major branches of the portal vein or to other parts of the liver (911). It is believed that de novo development of primary HCC in the remnant liver occurs with a lower frequency (12,13). Recurrence by metastasis seems to occur mainly in an early period, i.e., within the first two years after resection, whereas recurrence due to new primary lesions often occurs after a longer period (5,1417). Consistently, Chen et al. found that tumors that recurred late often showed clonal origins different from the original tumors, suggesting a de novo second primary HCC (18). The comparison of early and late recurrence of HCC after hepatectomy revealed that early recurrence is IV-23 associated with non-anatomical resection, microscopic vascular invasion and high alpha fetoprotein (AFP) levels (14). In contrast, late recurrence is associated with the level of chronic hepatitis, multi-nodularity, and tumor classification (14). In a recent pilot study, we identified a metastasis signature consisting of 153 genes that could distinguish HCC patients with portal venous metastases from those without (19). This metastasis signature was developed based on cDNA microarray profiling of 20 well-defined HCC cases, of which 10 presented with tumor thrombi in the major branches of the portal vein at surgery while 10 were metastasis-free HCC patients at the time of surgery and at follow-up. In this study, we IV-23 used two independent cohorts consisting of a total of 386 HCC patients to analyze IV-23 the utility of this signature as a risk classifier for HCC recurrence and survival. == MATERIALS AND METHODS == == Study Cohorts and Patient Characteristics == Cohort-1 hepatic tissues were obtained.