No abstract

The heterogeneous nature of hepatocellular carcinoma (HCC) and the lack of appropriate biomarkers have hampered patient prognosis and treatment stratification. Recently, we have identified that a hepatic stem cell marker, epithelial cell adhesion molecule (EpCAM), may serve as an early biomarker of HCC because its expression is highly elevated in premalignant hepatic tissues and in a subset of HCC. In this study, we aimed to identify novel HCC subtypes that resemble certain stages of liver lineages by searching for EpCAM-coexpressed genes. A unique signature of EpCAM-positive HCCs was identified by cDNA microarray analysis of 40 HCC cases and validated by oligonucleotide microarray analysis of 238 independent HCC cases, which was further confirmed by immunohistochemical analysis of an additional 101 HCC cases. EpCAM-positive HCC displayed a distinct molecular signature with features of hepatic progenitor cells including the presence of known stem/progenitor markers such as cytokeratin 19, c-Kit, EpCAM, and activated Wnt-B-catenin signaling, whereas EpCAM-negative HCC displayed genes with features of mature hepatocytes. Moreover, EpCAM-positive and EpCAM-negative HCC could be further subclassified into four groups with prognostic implication by determining the level of A-fetoprotein (AFP). These four subtypes displayed distinct gene expression patterns with features resembling certain stages of hepatic lineages. Taken together, we proposed an easy classification system defined by EpCAM and AFP to reveal HCC subtypes similar to hepatic cell maturation lineages, which may enable prognostic stratification and assessment of HCC patients with adjuvant therapy and provide new insights into the potential cellular origin of HCC and its activated molecular pathways. [Cancer Res 2008;68(5):1451-61]

Hepatocellular carcinoma (HCC) is an aggressive malignancy mainly due to metastases or postsurgical recurrence. We postulate that metastases are influenced by the liver microenvironment. Here, we show that a unique inflammation/immune response-related signature is associated with noncancerous hepatic tissues from metastatic HCC patients. This signature is principally different from that of the tumor. A global Th1/Th2-like cytokine shift in the venous metastasis-associated liver microenvironment coincides with elevated expression of macrophage colony-stimulating factor (CSF1). Moreover, a refined 17 gene signature was validated as a superior predictor of HCC venous metastases in an independent cohort, when compared to other clinical prognostic parameters. We suggest that a predominant humoral cytokine profile occurs in the metastatic liver milieu and that a shift toward anti-inflammatory/immune-suppressive responses may promote HCC metastases.

MicroRNAs (miRNAs) have been used as cancer-related biomarkers. Hepatocellular carcinoma (HCC) is an aggressive cancer with a dismal outcome largely due to metastasis and postsurgical recurrence. We investigated whether the expression of certain miRNAs are associated with HCC metastasis. We examined the miRNA expression profiles of 482 cancerous and noncancerous specimens from radical resection of 241 patients with HCC. Using a supervised algorithm and a clinically well-defined cohort of 131 cases, we built a unique 20-miRNA metastasis signature that could significantly predict (P < 0.001) primary HCC tissues with venous metastases from metastasis-free solitary tumors with 10-fold crossvalidation. However, significant miRNAs could not be identified from the corresponding noncancerous hepatic tissues. A survival risk prediction analysis revealed that a majority of the metastasis-related miRNAs were associated with survival. Furthermore, the 20-miRNA tumor signature was validated in 110 additional cases as a significant independent predictor of survival (P ‫؍‬ 0.009) and was significantly associated with both survival and relapse in 89 cases of early stage HCC (P ‫؍‬ 0.022 and 0.002, respectively). These 20 miRNAs may provide a simple profiling method to assist in identifying patients with HCC who are likely to develop metastases/recurrence. In addition, functional analysis of these miRNAs may enhance our biological understanding of HCC metastasis. (HEPATOLOGY 2008;47:897-907.) H epatocellular carcinoma (HCC) represents an extremely poor prognostic cancer that remains one of the most common and aggressive human malignancies worldwide. 1,2 The dismal outcome has been attributed to the major hallmarks of HCC, intrahepatic metastases or postsurgical recurrence. New tumor colonies frequently invade into the major branches of the portal vein and possibly other parts of the liver. 3-6 Resection or liver transplantation are the best options for a potential cure; however, only about 10%-20% of patients with HCC, defined by parameters of relatively normal liver function and a manageable tumor lesion as determined by the available clinical staging systems, are currently eligible for surgical intervention. Moreover, patients who were resected often have a high frequency of metastasis/recurrence, and postoperative 5-year survival is only 30%-40%.Metastasis is a complex process that involves multiple alterations. 7,8 Our understanding of such complexity has been improved by the advent of global microarray technology which allows for the molecular profiling of changes in gene expression that are associated with particular phenotypes, such as metastasis. In fact, several arraybased metastasis markers have also been demonstrated to be useful as prognostic molecular biomarkers, potentially offering additional tools for advanced diagnosis of HCC. For example, using complementary DNA (cDNA) microarray technology, we developed a unique tumor messenger RNA (mRNA) gene expression signature to predict prognosis and metastasis in pati...