Genetic and epigenetic alterations of RIZ1 and the correlation to clinicopathological parameters in liver fluke-related cholangiocarcinoma

Cholangiocarcinoma and liver transplantation: What we know so far?

Cholangiocarcinoma (CCA) is a type of cancer with increasing prevalence around the world that originates from cholangiocytes, the epithelial cells of the bile duct. The tumor begins insidiously and is distinguished by high grade neoplasm, poor outcome, and high risk for recurrence. Liver transplantation has become broadly accepted as a treatment option for CCA. Liver transplantation is expected to play a crucial role as palliative and curative therapy for unresectable hilar CCA and intrahepatic CCA. The purpose of this study was to determine which cases with CCA should be subjected to liver transplantation instead of resection, although reported post-transplant recurrence rate averages approximately 20%. This review also aims to highlight the molecular current frontiers of CCA and directions of liver transplantation for CCA.

Detecting cholangiocarcinoma in patients with primary sclerosing cholangitis - The promise of DNA methylation and molecular biomarkers

Cholangiocarcinoma (CCA) is a highly fatal malignancy of the bile ducts that arises in up to 20% of patients with primary sclerosing cholangitis (PSC). Current detection methods for CCA display suboptimal sensitivity and/or specificity, and there is no evidence-based screening strategy for CCA in patients with PSC. Consequently, CCA is often detected too late for surgical resection, contributing to the high mortality associated with this malignancy. Recently, biomarkers have emerged with potential to complement current detection methods, and/or be used for cancer surveillance in high-risk patient groups, including patients with PSC. Aberrant DNA methylation patterns represent promising biomarkers with great potential for CCA detection. Such aberrations are frequent in CCA, often occur early, and can be detected in liquid biopsies, including blood, bile and urine. This review summarises and highlights the most promising DNA methylation biomarkers identified for CCA detection so far, focusing on patients with PSC. Other promising molecular biomarkers for detection of PSC-associated CCA in liquid biopsies will also be briefly covered.

A deletion polymorphism in the RIZ gene is associated with increased progression of imatinib treated chronic myeloid leukemia patients

RIZ1 encodes a retinoblastoma (Rb)-interacting zinc finger protein, is commonly lost or expressed at reduced levels in cancer cells. The RIZ1 gene locus commonly undergoes LOH in many cancers. Here, we analyzed Proline insertion-deletion polymorphism at amino acid position 704 in the RIZ1 gene and its association with CML. The RIZ1 pro-704 LOH genotypes were determined by AS-PCR in 100 CML patients among which 50 were in CP-CML, 25 in AP-CML, and 25 in BC-CML. Pro704 ins/del polymorphism (LOH) was detected in 27% CML patients. Proline ins-ins homozygosity, del-del homozygosity and ins-del heterozygosity was detected in 9%, 18%, and 73% CML patients compared with 3%, 3%, and 94% in healthy controls, respectively (p < .0003). A four-fold increased risk was found to be associated del-del genotype. We found a statistically significant association between RIZ1 LOH and stage (p > .01) and hematological resistance (p > .001). However, there were no correlations found with other clinical parameters like age, gender, thrombocytopia, type of BCR-ABL, and molecular response. Our findings suggest that proline 704 del-del homozygosity phenotype can play an important role in progression of CML.

Contribution of RIZ1 to regulation of proliferation and migration of a liver fluke-related cholangiocarcinoma cell

PURPOSE

Retinoblastoma-interacting zinc finger gene (RIZ1) is a tumor suppressor gene which is highly inactivated by promoter hypermethylation in patients with liver fluke-related cholangiocarcinoma (CCA). Epigenetic aberration of this gene might withdraw the ability to restrain tumor cell proliferation and migration. We aimed to define the role of RIZ1 on cell proliferation and migration in CCA cell line.

MATERIALS AND METHODS

Small interference RNA (siRNA) was used to knock down the expression of RIZ1 in a CCA-derived cell line in which cell proliferation and cell migration were performed.

RESULTS

A predominant nuclear localization of RIZ1 was observed. Reduction of RIZ1 by siRNA augmented cell proliferation and migration.

CONCLUSION

The result suggested that RIZ1 might play a role in regulating cell proliferation and migration in CCA. Reduction of RIZ1 expression may aggravate the progression of CCA.