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The development of hepatocellular carcinoma (HCC) is a complex process, and HCC arises from the accumulation of multiple genetic alterations leading to changes in the genomic landscape. Current advances in genomic technologies have revolutionized the search for genetic alterations in cancer genomes. Recent studies in which all coding exons in HCC were sequenced have shed new light on the genomic landscape of this malignant disease. Catalogues of these somatic mutations and systematic analysis of catalogued mutations will lead us to uncover candidate HCC driver genes, although further functional validation is needed to determine whether these genes play a causal role in the development of HCC. This review provides an overview of previously known oncogenes and new oncogene candidates in HCC that were uncovered from recent exome or whole-genome sequencing studies. This knowledge provides direction for future personalized treatment approaches for patients with HCC.
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New Advances in Canonical Wnt/β-Catenin Signaling in Cancer
Occult HBV infection can persist following HBsAg loss and be transmitted, but the virological features are not well defined.
Here we investigated 25 Korean patients who lost HBsAg during follow up, either spontaneously or subsequent to therapy.
Whereas subtype adr (genotype C) was found in 96% of HBsAg positive patients, 75 % of patients who lost HBsAg spontaneously were seemed to be infected with the ayw subtype with sequence similar to genotype D. Mutations in the major hydrophilic region (MHR) of HBsAg were found in 7 patients who lost HBsAg spontaneously. The mutations include T123S, M125I/N, C139R, D144E, V177A, L192F, and W196L, some of which have not been reported before. Functional analysis via transfection experiments indicate that the C139R and D144E mutations drastically reduced HBsAg antigenicity, while the Y225del mutation found in one interferon-treated patient impaired HBsAg secretion.
Lack of detectable HBsAg in patient serum could be explained by low level of ccc DNA in liver tissue, low antigenicity of the surface protein, or its secretion defect.
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Molecular diagnostic methods have enabled the rapid diagnosis of drug-resistant mutations in hepatitis B virus (HBV) and have reduced both unnecessary therapeutic interventions and medical costs. In this study we evaluated the analytical and clinical performances of the HepB Typer-Entecavir kit (GeneMatrix, Korea) in detecting entecavir-resistance-associated mutations.
The HepB Typer-Entecavir kit was evaluated for its limit of detection, interference, cross-reactivity, and precision using HBV reference standards made by diluting high-titer viral stocks in HBV-negative human serum. The performance of the HepB Typer-Entecavir kit for detecting mutations related to entecavir resistance was compared with direct sequencing for 396 clinical samples from 108 patients.
Using the reference standards, the detection limit of the HepB Typer-Entecavir kit was found to be as low as 500 copies/mL. No cross-reactivity was observed, and elevated levels of various interfering substances did not adversely affect its analytical performance. The precision test conducted by repetitive analysis of 2,400 replicates with reference standards at various concentrations showed 99.9% agreement (2398/2400). The overall concordance rate between the HepB Typer-Entecavir kit and direct sequencing assays in 396 clinical samples was 99.5%.
The HepB Typer-Entecavir kit showed high reliability and precision, and comparable sensitivity and specificity for detecting mutant virus populations in reference and clinical samples in comparison with direct sequencing. Therefore, this assay would be clinically useful in the diagnosis of entecavir-resistance-associated mutations in chronic hepatitis B.
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We aimed to determine the association between the co-expression patterns of Notch1, Snail, and p53 proteins (NSP) and the postoperative prognosis of hepatocellular carcinoma (HCC).
The immunoblot data for molecular expression (147 HCC/corresponding non-HCC tissues and 15 dysplastic nodules) and the sequencing data for p53 mutations (110 HCCs) were obtained from our previous study. Data analyses were restricted to cases with HCC differentiation grade III (n=47), due to its high p53 mutation rate.
Nineteen of the 47 patients (40.4%) -comprising 12 in the liver and 7 in distant organs-had relapsed at 1-2 years after surgery. There was no relationship between p53 mutation and postoperative recurrence in the grade III HCCs. Seven (87.5%) of the eight relapsed cases with Notch1, Snail, and p53 (wild) co-expression experienced recurrence only within the liver, and all tumors were smaller than 5 cm in diameter. Extrahepatic relapse occurred mostly in HCC patients with tumors larger than 5 cm in diameter, without any deviation in the NSP pattern.
The results of this preliminary study suggest that the co-expression of Notch1, Snail, and p53 (wild) is not inferior to the patterns with p53 mutation as an indicator of postoperative recurrence of grade III HCC.
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