Contrast enhanced CT imaging offered crucial evidence not only for the diagnosis of gallstone ileus but also for decision making in management strategy.

BACKGROUND. The secreted frizzled‐related protein 1 gene (SFRP1) encodes a Wnt/β‐catenin signaling antagonist and frequently is inactivated by promoter methylation in many tumors. However, the role of SFRP1 in hepatocellular carcinoma (HCC) is not clear. Therefore, the authors investigated whether methylation of the SFRP1 promoter is common in HCC and whether it may influence SFRP1 expression. METHODS. Four HCC cell lines, 54 HCCs, 42 cirrhotic livers, 21 livers with chronic hepatitis, and 15 normal control tissues were analyzed for 1) SFRP1 promoter methylation by using methylation‐specific polymerase chain reaction analysis and bisulfite sequencing, 2) SFRP1 messenger RNA expression by using quantitative reverse transcriptase‐polymerase chain reaction analysis, and 3) loss of heterozygosity (LOH) by using microsatellite markers flanking the SFRP1 locus. HCC cells were treated with the demethylating agent 5‐aza‐2′‐deoxycytidine to determine whether it could restore SFRP1 expression. RESULTS. SFRP1 promoter methylation was observed in 75%, 48.2%, 21.4%, 14.3% and 0% in HCC cell lines, primary HCCs, cirrhotic livers, livers with chronic hepatitis, and normal control tissues, respectively. Methylation of the SFRP1 promoter region in HCCs increased significantly compared with control tissues. All samples with SFRP1 methylation showed down‐regulation of SFRP1 expression. Demethylation treatment with 5‐aza‐2′‐deoxycytidine in HCC cells restored SFRP1 expression. Moreover, LOH of markers D8S505 and D8S1722 was found in 25% and 27.6% of the informative samples, respectively. CONCLUSIONS. The current results suggested that promoter hypermethylation of SFRP1 is a common event in HCC and plays an important role in the regulation of SFRP1 expression. In addition to methylation‐mediated down‐regulation of SFRP1, LOH also may play a role. Cancer 2006. © 2006 American Cancer Society.

Oncogenic activation of the Wnt/b-catenin signaling pathway is common in hepatocellular carcinoma (HCC). The secreted frizzled-related proteins (SFRPs) function as negative regulators of Wnt signaling and have important implications for carcinogenesis. Promoter hypermethylation of SFRP genes is common in human cancers. However, the role of SFRPs in HCC is not clear. Recently, we have shown that SFRP1 is frequently downregulated through promoter hypermethylation. To confirm and extend these findings, the methylation status of the other SFRP members, including SFRP2, SFRP4 and SFRP5, was examined by methylation-specific polymerase chain reaction (MS-PCR). Hypermethylation of SFRP genes, except for SFRP4, is frequent in HCCs and the levels found here were significantly higher than those seen in cirrhotic livers, chronic hepatitis livers and normal controls (p < 0.0001 for SFRP1 and SFRP2, p < 0.05 for SFRP5). To investigate the role of SFRP1 in HCCs, we used re-expression of SFRP1 in bcatenin-dependent HCC cell lines: Huh6 and HepG2. Restoration of SFRP1 attenuated Wnt signaling in those Huh6 hepatoma cells with a b-catenin gene point mutation, decreased abnormal accumulation of b-catenin in the nucleus and suppressed cell growth. Conversely, restoration of SFRP1 in HepG2 hepatoma cells with truncated bcatenin could not block the Wnt signaling pathway. Furthermore, knocking down SFRP1 by RNA interference in b-catenin-deficient cell lines (SK-Hep1) stimulated Wnt signaling and promoted cell growth. Our data suggested that SFRP1 suppressed liver cancer cells growth through Wnt canonical signaling. Moreover, b-cateninindependent noncanonical pathway might be involved in Wnt signaling activation through unknown molecules in HCC. ' 2007 Wiley-Liss, Inc.Key words: epigenetic inactivation; hepatocellular carcinoma; SFRP1; Wnt/b-catenin Hepatocellular carcinoma (HCC) is one of the most common malignant human tumors worldwide. 1-4 The major factors associated with HCC include chronic hepatitis B and C viral infections, chronic alcohol consumption, aflatoxin-B1-contaminated food and virtually all cirrhosis-inducing conditions. 4 Other etiological factors have also been proposed to lead to HCC. In addition, gender can also influence the risk and behavior of HCC, with men accounting for more cases. 5 The molecular mechanisms of hepatocarcinogenesis and the complex interactions of genetic factors remain to be elucidated.Wnt glycoproteins comprise a family of extracellular signaling ligands that play essential roles in proliferation, patterning and fate determination during normal developmental processes. [6][7][8][9][10][11][12] Although this signaling is critical for normal embryonic development, the aberrant of activation of the Wnt signal transduction pathway has been closely linked to tumorigenesis in adults. [13][14][15] b-Catenin is a crucial downstream component of the Wnt signaling pathway. When Wnt signaling is engaged, the adenomatosis polyposis coli (APC) and Axin proteins no longer bind b-catenin, with consequent b...