gamma-Carboxyglutamic acid content of hepatocellular carcinoma-associated des-gamma-carboxy prothrombin

Current status and new directions for hepatocellular carcinoma diagnosis

Liver cancer ranks as the sixth most common cancer globally, with hepatocellular carcinoma (HCC) accounting for approximately 75%-85% of cases. Most patients present with moderately advanced disease, while those with advanced HCC face limited and ineffective treatment options. Despite diagnostic efforts, no ideal tumor marker exists to date, highlighting the urgent clinical need for improved early detection of HCC. A key research objective is the development of assays that target specific pathways involved in HCC progression. This review explores the pathological origin and development of HCC, providing insights into the mechanistic rationale, clinical statistics, and the advantages and limitations of commonly used diagnostic tumor markers. Additionally, it discusses the potential of emerging biomarkers for early diagnosis and offers a brief overview of relevant assay methodologies. This review aims to summarize existing markers and investigate new ones, providing a basis for subsequent research.

Combined Hounsfield units of hepatocellular carcinoma on computed tomography and PET as a noninvasive predictor of early recurrence after living donor liver transplantation: Time-to-recurrence survival analysis

BACKGROUND

Liver transplantation is an effective treatment for preventing hepatocellular carcinoma (HCC) recurrence. This retrospective study aimed to quantitatively evaluate the attenuation in Hounsfield units (HU) on contrast-enhanced computed tomography (CECT) as a prognostic factor for hepatocellular carcinoma (HCC) following liver transplantation as a treatment. Our goal is to optimize its predictive ability for early tumor recurrence and compare it with the other imaging modality-positron emission tomography (PET).

METHODS

In 618 cases of LDLT for HCC, only 131 patients with measurable viable HCC on preoperative CECT and preoperative positron emission tomography (PET) evaluations were included, with a minimum follow-up period of 6 years. Cox regression models were developed to identify predictors of postoperative recurrence. Performance metrics for both CT and PET were assessed. The correlation between these two imaging modalities was also evaluated. Survival analyses were conducted using time-dependent receiver operating characteristic (ROC) curve analysis and area under the curve (AUC) to assess accuracy and determine optimized cut-off points.

RESULTS

Univariate and multivariate analyses revealed that both arterial-phase preoperative tumor attenuation (HU) and PET were independent prognostic factors for recurrence-free survival. Both lower arterial tumor enhancement (Cut-off value = 59.2, AUC 0.88) on CT and PET positive (AUC 0.89) increased risk of early tumor recurrence 0.5-year time-dependent ROC. Composites with HU < 59.2 and a positive PET result exhibited significantly higher diagnostic accuracy in detecting early tumor recurrence (AUC = 0.96).

CONCLUSION

Relatively low arterial tumor enhancement values on CECT effectively predict early HCC recurrence after LDLT. The integration of CT and PET imaging may serve as imaging markers of early tumor recurrence in HCC patients after LDLT.

Preclinical human and murine models of hepatocellular carcinoma (HCC)

Hepatocellular carcinoma (HCC) is the most frequent liver cancer, which account for more than 90 % of all liver cancer cases. It is the fifth leading cause of cancer globally and the second leading cause of cancer-related mortality in men. The availability of competent HCC preclinical models is fundamental to the success of mechanistic studies, molecular target identification, and drug testing. However, there are challenges associated with the use of these models. In this review, we provided updates on various cell lines, animals, and human HCC models, their specific preclinic use and associated potential challenges. Overall, the understanding of the merits and demerits of a particular HCC model will improve model selection for various preclinical studies.

Measuring serum prothrombin in patients treated with warfarin or direct oral anticoagulants

BACKGROUND

Warfarin therapy influences generation of γ-carboxyglutamyl (Gla) residues in prothrombin, causing reduced coagulation activity. It will leave such inactive prothrombin in serum after clot formation, resulting in serum prothrombin constituting total inactive prothrombin in these patients.

METHODS

An ELISA was developed to measure biologically inactive prothrombin in serum, and applied to serum from warfarin therapy causing a decrease in Gla residues or direct oral anticoagulant (DOAC) therapy as its contrast.

RESULTS

The concentrations of serum prothrombin in both the warfarin and DOAC groups were higher than those in the healthy group (p < 0.01 and p < 0.001, respectively). When serum in the previous three groups was treated with barium carbonate to exclude prothrombin, which lost several Gla residues, the prothrombin concentration in the DOAC group decreased to the same level as that in the healthy group, indicating that prothrombin was obtained at a high level only in the warfarin group (p < 0.01).

CONCLUSIONS

Warfarin and DOAC led to increase in serum prothrombin concentration. The reason is that DOAC decreases prothrombin recruitment during fibrin clot formation, while warfarin leads to the accumulation of inactive prothrombin, which have a decreased number of Gla residues.

Inclusive Quantification Assay of Serum Des-γ-Carboxyprothrombin Proteoforms for Hepatocellular Carcinoma Surveillance by Targeted Mass Spectrometry

Hepatocellular carcinoma (HCC) is a malignant cancer with one of the highest mortality rates. Des-γ-carboxyprothrombin (DCP) is an HCC serologic surveillance marker that can complement the low sensitivity of alpha-fetoprotein (AFP). DCP exists in the blood as a mixture of proteoforms from an impaired carboxylation process at glutamic acid (Glu) residues within the N-terminal domain. The heterogeneity of DCP may affect the accuracy of measurements because DCP levels are commonly determined using an immunoassay that relies on antibody reactivity to an epitope in the DCP molecule. In this study, we aimed to improve the DCP measurement assay by applying a mass spectrometry (MS)-based approach for a more inclusive quantification of various DCP proteoforms. We developed a multiple-reaction monitoring-MS (MRM-MS) assay to quantify multiple noncarboxylated peptides included in the various des-carboxylation states of DCP. We performed the MRM-MS assay in 300 patients and constructed a robust diagnostic model that simultaneously monitored three noncarboxylated peptides. The MS-based quantitative assay for DCP had reliable surveillance power, which was evident from the area under the receiver operating characteristic curve (AUROC) values of 0.874 and 0.844 for the training and test sets, respectively. It was equivalent to conventional antibody-based quantification, which had AUROC values at the optimal cutoff (40 mAU/mL) of 0.743 and 0.704 for the training and test sets, respectively. The surveillance performance of the MS-based DCP assay was validated using an independent validation set consisting of 318 patients from an external cohort, resulting in an AUROC value of 0.793. Conclusion: Due to cost effectiveness and high reproducibility, the quantitative DCP assay using the MRM-MS method is superior to antibody-based quantification and has equivalent performance.

Novel biomarkers for the management of chronic hepatitis B

Hepatitis B virus (HBV) cannot be eliminated completely from infected hepatocytes because of the presence of intrahepatic covalently closed circular DNA (cccDNA). As chronic hepatitis B (CHB) can progress to cirrhosis and hepatocellular carcinoma (HCC), it is important to manage CHB to prevent HCC development in high-risk patients with high viral replicative activity or advanced fibrosis. Serum biomarkers are noninvasive and valuable for the management of CHB. Hepatitis B core-related antigen (HBcrAg) correlates with serum HBV DNA and intrahepatic cccDNA. In CHB patients with undetectable serum HBV DNA or loss of HBsAg, HBcrAg still can be detected and the decrease in HBcrAg levels is significantly associated with hopeful outcomes. Therefore, HBcrAg can predict HCC occurrence or recurrence. Measurement of the Mac-2 binding protein glycosylation isomer (M2BPGi) has been introduced for the evaluation of liver fibrosis. Because elevated M2BPGi in CHB is related to liver fibrosis and the prediction of HCC development, monitoring its progression is essential. Because alpha fetoprotein (AFP) has insufficient sensitivity and specificity for early-stage HCC, a combination of AFP plus protein induced by vitamin K absence factor II, or AFP plus Lens culinaris agglutinin-reactive fraction of alpha-fetoprotein might improve the diagnosis of HCC development. Additionally, Dickkopf-1 and circulating immunoglobulin G antibodies are the novel markers to diagnose HCC or assess HCC prognosis. This review provides an overview of novel HBV biomarkers used for the management of intrahepatic viral replicative activity, liver fibrosis, and HCC development.

The correlation and role analysis of COL4A1 and COL4A2 in hepatocarcinogenesis

Liver fibrosis biomarker, Type IV collagen, may function as hepatocarcinogenesis niche. However, among the six isoforms, the isoforms providing tumor microenvironment and their regulatory network are still unclarified. Based on bioinformatics analysis of hundreds of HCC transcriptome datasets from public databases, we found that COL4A1/2 expressions were significantly correlated with hepatocarcinogenesis, progression, and prognosis. The expressions of COL4A1/2 were significantly upregulated in the preneoplastic and HCC tissues compared with normal tissues. Moreover, the overexpression of COL4A2 was highly correlated with shorter progression-free survival in HCC patients. Bioinformatics analysis also generates an interactive regulatory network in which COL4A1/2 directly binding to integrin alpha-2/beta-1 initiates a sequentially and complicated signaling transduction, to accelerate cell cycle and promote tumorigenesis. Among those pathways, the PI3K-Akt pathway is significantly enriched in cooperative mutations and correlation analysis. This suggests that the key activated signaling is PI3K-Akt pathway which severing as the centerline linked with other pathways (Wnt and MAPK signaling) and cell behaviors signaling (cell cycle control and cytoskeleton change). Switching extracellular matrix collagen isoform may establish pro-tumorigenic and metastatic niches. The findings of COL4A1/2 and related signaling networks are valuable to be further investigated that may provide druggable targets for HCC intervention.

Current status of hepatocellular carcinoma detection: screening strategies and novel biomarkers

Hepatocellular carcinoma (HCC) remains a major cause of cancer-related mortality worldwide. Delayed diagnosis is a major factor responsible for the poor prognosis of HCC. Several advances have been made in the field of liver imaging with the use of novel imaging contrasts, improving current imaging techniques with contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI), introduction of new technologies such as contrast liver ultrasound, and development of novel biomarkers with the goal of early detection of HCC and improving outcomes of patients with HCC. This review focuses on current surveillance strategies and development of biomarkers with the goal of early detection of HCC.

Hepatocellular Carcinoma: Causes, Mechanism of Progression and Biomarkers

Hepatocellular Carcinoma (HCC) is one of the most common malignant tumours in the world. It is a heterogeneous group of a tumour that vary in risk factor and genetic and epigenetic alteration event. Mortality due to HCC in last fifteen years has increased. Multiple factors including viruses, chemicals, and inborn and acquired metabolic diseases are responsible for its development. HCC is closely associated with hepatitis B virus, and at least in some regions of the world with hepatitis C virus. Liver injury caused by viral factor affects many cellular processes such as cell signalling, apoptosis, transcription, DNA repair which in turn induce important effects on cell survival, growth, transformation and maintenance. Molecular mechanisms of hepatocellular carcinogenesis may vary depending on different factors and this is probably why a large set of mechanisms have been associated with these tumours. Various biomarkers including α-fetoprotein, des-γ-carboxyprothrombin, glypican-3, golgi protein-73, squamous cell carcinoma antigen, circulating miRNAs and altered DNA methylation pattern have shown diagnostic significance. This review article covers up key molecular pathway alterations, biomarkers for diagnosis of HCC, anti-HCC drugs and relevance of key molecule/pathway/receptor as a drug target.

Myeloma-Derived Light Chain Paired with a Diagnostic Monoclonal Antibody Hinders Immunoassay Performance

Monoclonal antibodies are widely used as the capture and detection reagents in diagnostic immunoassays. In the past, myeloma fusion partners expressing endogenous heavy and/or light chains were often used to generate hybridoma cell lines. As a result, mixed populations of antibodies were produced that can cause inaccurate test results, poor antibody stability, and significant lot-to-lot variability. We describe one such scenario where the P3U1 (P3X63Ag8U.1) myeloma fusion partner was used in the generation of a hybridoma producing protein induced vitamin K absence/antagonist-II (PIVKA II) antibody. The hybridoma produces three subpopulations of immunoglobulin as determined by ion exchange (IEx) chromatography that exhibit varying degrees of immunoreactivity (0%, 50%, or 100%) to the target antigen as determined by Surface Plasmon Resonance. To produce an antibody with the highest possible sensitivity and specificity, the antigen-specific heavy and light chain variable domains (VH and VL) were cloned from the hybridoma and tethered to murine IgG1 and kappa scaffolds. The resulting recombinant antibody was expressed in Chinese hamster ovary cells and is compatible for use in a diagnostic immunoassay.

Biomarkers for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer deaths worldwide. The HCC diagnosis is usually achieved by biomarkers, which can also help in prognosis prediction. Furthermore, it might represent certain therapeutic interventions through some combinations of biomarkers. Here, we review on our current understanding of HCC biomarkers.

A quantitative analytical method for PIVKA-II using multiple reaction monitoring-mass spectrometry for early diagnosis of hepatocellular carcinoma

Prothrombin induced by vitamin K absence-II (PIVKA-II) is an effective tumor marker for hepatocellular carcinoma (HCC). We have developed a novel targeted mass spectrometric (MS) assay for quantifying PIVKA-II in human serum. The ideal signature peptide was selected to measure PIVKA-II concentrations on a triple quadrupole (QqQ) mass spectrometer, and the chromatography gradient was optimized for the peptide separation to minimize elution interference. Using multiple reaction monitoring-mass spectrometry (MRM-MS), good linearity (R ² = 0.9988) was obtained for PIVKA-II over a range of 3 orders. We achieved a limit of detection (LOD) of 0.45 nM (31.72 ng/mL), a limit of quantification (LOQ) of 0.93 nM (65.31 ng/mL), a lower limit of quantification (LLOQ) of 0.49 nM (34.32 ng/mL), and an upper limit of quantification (ULOQ) of 1000.00 nM (70,037.00 ng/mL). The intra-day and inter-day precisions were within ±14.96%, and the accuracy ranged from 87.66 to 114.29% for QC samples at four concentrations. Compared with an established immunoassay, the correlation (R = 0.8335) was good for the measurements of PIVKA-II concentrations. This method was successfully applied to the analysis of clinical samples for normal control (n = 50), chronic hepatitis (n = 50), liver cirrhosis (n = 50), HCC (n = 50), and recovery (n = 50) serum. Graphical Abstract MRM-MS assay development for determining concentration of PIVKA-II in serum and a comparison between MRM-MS assay and immunoassay with high correlation.

Clinical application of protein induced by vitamin K antagonist-II as a biomarker in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the third leading cause of cancer deaths worldwide. Early diagnosis improves the prognosis. Protein induced by vitamin K antagonist-II (PIVKA-II) is an effective serum biomarker for HCC diagnosis and prognosis. Combined with another serum biomarker α-fetoprotein (AFP), the sensitivity and specificity of HCC diagnosis can be improved to a maximum of 94 and 98.5 %, respectively. PIVKA-II alone or in combination with AFP and/or AFP-L3 was effective in predicting the treatment response and clinical outcome of curative hepatic resection, chemotherapy, targeted therapy, radiotherapy, and liver transplantation. Japanese clinical guidelines recommend the combined use of PIVKA-II and AFP for the diagnosis of HCC, management of high-risk population, and prognosis of anticancer treatment. Further, PIVKA-II as a functional target promoted HCC cell proliferation, invasion, and metastasis by activating c-Met and other signal transduction pathways. Inhibition of PIVKA-II may provide a selective and effective therapy for HCC.

Roles and Signaling Pathways of Des-γ-Carboxyprothrombin in the Progression of Hepatocellular Carcinoma

Des-γ-carboxyprothrombin (DCP), an abnormal prothrombin produced in human hepatocellular carcinoma (HCC), plays crucial roles in the progression of HCC. DCP binding to cellular mesenchymal-epithelial transition factor (c-Met) is an initial event and consequently stimulates HCC through the increase of c-Met-Janus kinase 1- signal transducers and activators of transcription pathways. DCP stimulates HCC invasion through activation of matrix metalloproteinase via upregulation of extracellular signal-regulated kinase-mitogen-activated protein kinase (MAPK) pathway. DCP stimulates HCC angiogenesis through activation of the DCP-kinase insert domain receptor-phospholipaseC-γ-MAPK pathway. Identification of these pathways is important for designing the therapeutic strategy for HCC.

The influence of alcoholic liver disease on serum PIVKA-II levels in patients without hepatocellular carcinoma

Background/Aims

Prothrombin induced by vitamin K deficiency or antagonist II (PIVKA-II) is a widely used diagnostic marker for hepatocellular carcinoma (HCC). We evaluated the correlation between alcoholic liver disease (ALD) and serum PIVKA-II levels in chronic liver disease (CLD) patients.

Methods

We retrospectively reviewed the medical records of 2,528 CLD patients without HCC. Among these patients, 76 exhibited serum high PIVKA-II levels of >125 mAU/mL (group 1). We categorized 76 control patients matched by age, sex, and the presence of liver cirrhosis from the remaining patients who were negative for serum PIVKA-II (group 2).

Results

Group 1 revealed increased antibiotic usage (23.7% vs 2.6%, p<0.001) and incidence of ALD (60.5% vs 14.5%, p<0.001) as well as elevated aspartate aminotransferase (52.5 IU/L vs 30.5 IU/L, p=0.025) and γ glutamyl transpeptidase (67.5 IU/L vs 36.5 IU/L, p=0.005) levels compared with group 2. Further, group 1 was significantly associated with a worse Child-Pugh class than group 2. In the multivariate analysis, ALD (odds ratio [OR], 7.151; p<0.001) and antibiotic usage (OR, 5.846; p<0.001) were significantly associated with positive PIVKA-II levels.

Conclusions

Our study suggests that ALD and antibiotics usage may be confounding factors when interpreting high serum PIVKA-II levels in patients without HCC. Therefore, serum PIVKA-II levels in patients with ALD or in patients administered antibiotics should be interpreted with caution.

Des-γ-carboxyprothrombin (DCP) and NX-DCP expressions and their relationship with clinicopathological features in hepatocellular carcinoma

Aim

Des-γ-carboxyprothrombin (DCP) has been used as a tumor marker for hepatocellular carcinoma (HCC). Recently the DCP/NX-DCP ratio, calculated by dividing DCP by NX-DCP, has been reported useful in detecting HCC. The purpose of this study is to clarify the significance of DCP and NX-DCP expression in HCC tissues.

Methods

HCC and non-HCC tissue samples were obtained from 157 patients and were immunohistochemically examined for DCP and NX-DCP expression using anti-DCP antibody and anti-NX-DCP antibody. DCP and NX-DCP expression scores were calculated by multiplying staining intensity grade by percentage of stained area. Serum DCP and NX-DCP levels were determined in 89 patients. We evaluated the relationship between tumor expression, serum level, and pathomorphological findings.

Results

Intrahepatic metastasis (im) was significantly more frequent in cases with high DCP expression than in cases with low DCP expression. High NX-DCP expression was associated with significantly lower histological grade, and less frequent im or portal vein invasion (vp) than low NX-DCP expression. Serum DCP was correlated with DCP expression, but serum NX-DCP was not correlated with NX-DCP expression. DCP-positive (≥40 mAU/L), NX-DCP-positive (≥90 mAU/L), and DCP/NX-DCP ratio-positive (≥1.5) cases were associated with significantly larger tumor size and more frequent vp than negative cases. DCP was rarely expressed, but NX-DCP was frequently expressed in non-cancerous liver tissues. Patients with NX-DCP expression-negative tumors showed a lower survival rate than those with NX-DCP expression-positive tumors (p = 0.04), whereas the survival in serum NX-DCP-positive cases was lower than that of serum negative cases (p = 0.02).

Conclusions

DCP and NX-DCP were produced in HCC tissues, but differed in expression level and biological properties. DCP expression, serum DCP or NX-DCP level, and DCP/NX-DCP ratio were closely related to malignant properties of HCC.

Novel des-γ-carboxy prothrombin in serum for the diagnosis of hepatocellular carcinoma

BACKGROUND AND AIM

Serum des-γ-carboxy prothrombin (DCP) levels using a newly developed electrochemiluminescence immunoassay (ECLIA, novel DCP [NX-DCP]) were measured, and the utility of NX-DCP and DCP/NX-DCP ratio for the diagnosis of hepatocellular carcinoma (HCC) was investigated. Antigenic differences in DCP between HCC and non-HCC patients were elucidated.

METHODS

The subjects included 170 patients with HCC, 61 with benign liver disease, 12 with obstructive jaundice, and 10 warfarin users. NX-DCP was quantitated by sandwich ECLIA employing novel anti-DCP monoclonal antibodies, P11 and P16. Conventional DCP was quantitated by standard ECLIA. DCP extracted from serum by affinity-chromatography was analyzed by Western blotting.

RESULTS

Conventional serum DCP levels were high in patients with HCC and obstructive jaundice, and in warfarin users, consistent with previous reports. Serum NX-DCP levels were high only in warfarin users and obstructive jaundice patients (vitamin K-deficient patients) but not in HCC patients. The DCP/NX-DCP ratio was significantly higher in the HCC group than in the benign liver disease, obstructive jaundice, and warfarin groups (P < 0.001). Receiver operating characteristic analysis showed significant superiority of the DCP/NX-DCP ratio over conventional DCP as a marker for HCC diagnosis (P < 0.05). Western blot analysis showed that P11 and P16 reacted strongly with DCP from a warfarin user and an obstructive jaundice patient but very faintly with DCP from an HCC patient. Immunohistochemistry on HCC samples and autopsied normal liver tissues from warfarin users showed similar results.

CONCLUSIONS

The DCP/NX-DCP ratio is very useful for diagnosing HCC. DCP in HCC patients is distinct from that in vitamin K-deficient patients.

Tumor markers for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors with a high rate of morbidity and mortality. HCC affects approximately one million individuals annually worldwide, with the incidence equal to the mortality rate. In 2008, HCC was listed as the third most lethal cancer. Thus, early diagnosis is crucial for improving the survival rate for patients. α-fetoprotein (AFP) together with iconography and pathology detection are commonly used in the clinical early diagnosis of liver cancer. However, the specificity and sensitivity of AFP used in screening for liver cancer are not satisfactory. Athough the development of molecular biology has led to the identification of new tumor markers, including proteantigens, cytokines, enzymes and isoenzymes, as well as related genes that can be used in the treatment and prognosis of liver cancer, more tumor markers are required for effective early diagnosis of diseases and monitoring of the curative effect.

Des-γ-carboxy prothrombin ratio measured by P-11 and P-16 antibodies is a novel biomarker for hepatocellular carcinoma

Serum tumor markers, including α-fetoprotein (AFP) and des-γ-carboxy prothrombin (DCP), are currently used in the diagnosis of hepatocellular carcinoma (HCC). There is, however, an aberrant increase in serum DCP in patients with obstructive jaundice, vitamin K deficiency or who are taking warfarin, resulting from a problem with the current methodology for measurement of this marker. This study aimed to elucidate the utility of a new biomarker, NX-PVKA, for early diagnosis of HCC. A total of 96 patients were included in the HCC group. The control group included 138 liver cirrhosis (LC) patients without HCC. Serum concentrations of conventional DCP, AFP, AFP-L3 and NX-PVKA were measured. The NX-PVKA ratio was calculated by dividing DCP by NX-PVKA. In patients not taking warfarin, the area under the curve values of DCP, NX-PVKA ratio, AFP and AFP-L3 were 0.715, 0.690, 0.737 and 0.654, respectively, confirming the clinical utility of these markers in detecting HCC. In cases with DCP > 35 mAU/mL in particular, a significant increase in the NX-PVKA ratio was observed in patients with HCC. In those cases, the cut-off value for the NX-PVKA ratio that was optimized by the receiver operating characteristic (ROC) curve was 1.15. In addition, the sensitivity and specificity for diagnosing HCC were 69.2% and 75.9%, respectively. Patients with HCC had higher NX-PVKA ratios compared to patients with LC taking warfarin (P = 0.063). These results suggest that, when used in combination with DCP, the NX-PVKA ratio is a promising novel marker for the detection of HCC.

Des-gamma-carboxy prothrombin identified by P-11 and P-16 antibodies reflects prognosis for patients with hepatocellular carcinoma

BACKGROUND AND AIMS

Serum des-γ-carboxy prothrombin (DCP) is an established tumor marker in patients with hepatocellular carcinoma (HCC), which can be identified by using MU-3 antibody. The MU-3 antibody mainly reacts with the 9-10 glutamic acid residues of DCP (conventional DCP). Since other variants of DCP with fewer glutamic acid residues can be detected using P-11 and P-16 antibodies (code name: NX-PVKA), we examined the clinical characteristics associated with NX-PVKA, and whether NX-PVKA is a useful measure in HCC patients.

METHODS

Participants comprised 197 HCC patients admitted to our hospital between 2001 and 2010. NX-PVKA, conventional DCP, alpha-fetoprotein, and L3 fraction of alpha-fetoprotein were measured prior to initiation of HCC treatment.

RESULTS

Of the tumor markers assessed, NX-PVKA was the only significant predictor of prognosis (hazard ratio, 81.32; P < 0.0001). Patients with NX-PVKA level ≥ 100 mAU/mL showed significantly lower survival rates (P < 0.0001). NX-PVKA level was also significantly associated with platelet count, prothrombin time, C-reactive protein, sex, maximum tumor size, number of nodules, and portal venous invasion by HCC. Finally, using NX-PVKA level and other clinical parameters, we established a prognostic model to estimate patient survival time.

CONCLUSIONS

NX-PVKA offers the best marker of tumor prognosis among HCC patients, and is strongly associated with tumor factors and hepatic functional reserve. NX-PVKA could be useful for clinical evaluation of tumor severity, as well as the estimated duration of survival among patients with HCC.

Biomarkers for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) ranks high among the most common and fatal cancers in the world. HCC develops from chronic liver diseases, especially from hepatitis C virus-related and hepatitis B virus (HBV)-related liver diseases. In this sense, useful biomarkers for HCC detection for the patients at risk of HCC are quite important. Recently, new therapies for HCC have been developed, and the prognosis of the patients has improved. However, considering the recurrence rate of HCC after treatment is very high, biomarkers that detect recurrence at an early stage are also required. In addition, since new drugs such as multikinase inhibitors have been introduced to the clinical scene, surrogate biomarkers to predict the effectiveness of treatment will be required in the near future. So far, many biomarkers for HCC have been developed, and their clinical usefulness has been assessed. As a result, several biomarkers for HCC are widely used. However, investigations to discover more useful biomarkers that fit in clinical settings are under way. In this review article, biomarkers for HCC are overviewed to examine their clinical usefulness.

Novel method to measure serum levels of des-gamma-carboxy prothrombin for hepatocellular carcinoma in patients taking warfarin: a preliminary report

Des-gamma-carboxy prothrombin (DCP) is a useful tumor marker for hepatocellular carcinoma (HCC), but its utility is limited in patients taking vitamin K antagonists. We evaluated the NX-DCP ratio, a newly developed method to measure serum DCP, for its ability to identify DCP elevation induced by HCC in this patient subpopulation. Conventional DCP measurements and the NX-DCP ratio were compared in patients with and without HCC, all of whom were taking the vitamin K antagonist warfarin. We found no differences in conventional DCP measurements between patients with and without HCC due to warfarin treatment. In contrast, the NX-DCP ratio was significantly higher in patients with HCC; the NX-DCP ratio in all patients without HCC was <1.50. When the cut-off was fixed at 1.50, sensitivity and specificity for HCC diagnosis were 60.0% and 100.0%, respectively, which are comparable to those of conventional DCP measurements in patients not taking warfarin. The novel NX-DCP ratio identifies patients on warfarin with elevated DCP due to HCC and is useful as a tumor marker for HCC in this patient subpopulation.

Effect of vitamin K2 supplementation on functional vitamin K deficiency in hemodialysis patients: a randomized trial

BACKGROUND

Vascular calcification is a predictor of cardiovascular morbidity and mortality. Hemodialysis patients experience severe vascular calcifications. Matrix Gla protein (MGP) is a central calcification inhibitor of the arterial wall; its activity depends on vitamin K-dependent γ-glutamate carboxylation. Uncarboxylated MGP, formed as a result of vitamin K deficiency, is associated with cardiovascular disease. Recent studies suggest poor vitamin K status in hemodialysis patients. We therefore aimed to investigate whether daily vitamin K supplementation improves the bioactivity of vitamin K-dependent proteins in hemodialysis patients, assessed by circulating dephosphorylated-uncarboxylated MGP, uncarboxylated osteocalcin, and uncarboxylated prothrombin (PIVKA-II [protein induced by vitamin K absence II]).

STUDY DESIGN

Interventional randomized non-placebo-controlled trial with 3 parallel groups.

SETTING & PARTICIPANTS

53 long-term hemodialysis patients in stable conditions, 18 years or older. 50 healthy age-matched individuals served as controls.

INTERVENTIONS

Menaquinone-7 (vitamin K(2)) treatment at 45, 135, or 360 μg/d for 6 weeks.

OUTCOMES

Plasma levels of dephosphorylated-uncarboxylated MGP, uncarboxylated osteocalcin, and PIVKA-II.

MEASUREMENTS

Plasma levels were assessed using enzyme-linked immunosorbent assays.

RESULTS

At baseline, hemodialysis patients had 4.5-fold higher dephosphorylated-uncarboxylated MGP and 8.4-fold higher uncarboxylated osteocalcin levels compared with controls. PIVKA-II levels were elevated in 49 hemodialysis patients. Vitamin K(2) supplementation induced a dose- and time-dependent decrease in circulating dephosphorylated-uncarboxylated MGP, uncarboxylated osteocalcin, and PIVKA-II levels. Response rates in the reduction in dephosphorylated-uncarboxylated MGP levels were 77% and 93% in the groups receiving 135 μg and 360 μg of menaquinone-7, respectively.

LIMITATIONS

Small sample size.

CONCLUSIONS

This study confirms that most hemodialysis patients have a functional vitamin K deficiency. More importantly, it is the first study showing that inactive MGP levels can be decreased markedly by daily vitamin K(2) supplementation. Our study provides the rationale for intervention trials aimed at decreasing vascular calcification in hemodialysis patients by vitamin K supplementation.

Des-γ-carboxyl prothrombin induces matrix metalloproteinase activity in hepatocellular carcinoma cells by involving the ERK1/2 MAPK signalling pathway

Des-γ-carboxy prothrombin (DCP), an aberrant prothrombin produced by hepatocellular carcinoma (HCC) cells, has been shown to be associated with the biological malignant potential of HCC. The aim of this study was to evaluate the effect of DCP on HCC cell growth and metastasis, and to explore the underlying molecular mechanisms. DCP significantly stimulated HCC cell growth, as measured by cell counting kit-8 assay. Transwell chamber assay showed that DCP increased HCC cell migration through reconstituted extracellular matrix (Matrigel). Gelatin zymography assay and Western blot analysis demonstrated that DCP increased the secretion and expression of matrix metalloproteinase (MMP)-2 and MMP-9 in the supernatant of cultured HCC cells and on tumour cell membranes. DCP was found to bind to the cell surface receptor Met, resulting in Met phosphorylation and subsequent activation of the epidermal growth factor receptor (EGFR). Western blot analysis demonstrated that DCP stimulated a sequential kinase phosphorylation cascade including ERK1/2, MEK1/2 and c-Raf, indicating activation of the extracellular signal-regulated kinase/mitogen activated protein kinase (ERK1/2 MAPK) signalling pathway. Furthermore, blocking ERK1/2 MAPK activation with ERK1/2 inhibitor PD98059 essentially abolished the DCP-induced MMP-2 and MMP-9 activity, confirming the signalling pathway of DCP stimulation. Taken together, these results suggested that DCP stimulates HCC growth and promotes HCC metastasis by increasing the activity of MMP-2 and MMP-9 through activation of the ERK1/2 MAPK signalling pathway.

Clinical and molecular insights into the hepatocellular carcinoma tumour marker des-γ-carboxyprothrombin

Des-γ-carboxyprothrombin (DCP) is known as a tumour marker for hepatocellular carcinoma (HCC). Various tumour markers have been developed for serological diagnosis of cancers, including HCC, in order to increase the survival rate of cancer patients. The currently recommended combined testing of DCP and α-fetoprotein (AFP) or Lens culinaris agglutinin-reactive fraction of α-fetoprotein has been established to diagnose HCC. This combined testing using several tumour markers helps to increase the sensitivity of diagnosis of HCC, thus significantly increasing the clinical usefulness of DCP. The excessive production of DCP may be related to worse tumour behaviour, such as the presence of vascular invasion and intrahepatic metastasis of HCC cells. A high level of DCP was suggested to be useful as one of the factors in new recipient selection criteria of liver transplantation. The clinical use of DCP, therefore, might play a vital role in predicting tumour behaviour in patients with HCC. That said, the basic mechanism of DCP production has not been fully clarified. Various factors such as vitamin K(2) and γ-glutamyl carboxylase may contribute to the production of DCP and have a complex relationship. Moreover, recent studies have revealed that DCP functions as a growth factor and might play significant roles in cancer progression. Thus, DCP represents a potential target of drug discovery to establish new chemotherapeutic strategy for HCC. However, various issues have to be resolved to construct a novel therapy for HCC-targeting DCP. Innovation is required to make further progress in examining DCP.

Des-gamma-carboxy prothrombin stimulates human vascular endothelial cell growth and migration

Des-gamma-carboxy prothrombin (DCP) is an aberrant prothrombin produced by hepatocellular carcinoma (HCC) cells. Serum and tissue DCP expressions are thought to reflect the biological malignant potential of HCC. However, the role of DCP in the development of angiogenesis is not well understood. Herein, we report the effects of DCP on growth and migration of human vascular endothelial cells. DCP significantly stimulated the proliferation of HUVEC (ECV304) cells in a dose and time dependent manner, as measured by the MTT assay. A continuous rapid migration of ECV304 cells was observed in the presence of DCP measured by the scratch wound assay. The continuous rapid invasive activity, measured by transwell chamber assay also showed that DCP increased endothelial cells migration through the reconstituted extracellular matrix (Matrigel). Further, the tube formation of vascular endothelial cells on 3-D Matrigel showed an increased number of branch points of ECV304 cells induced by DCP in a dose dependent manner. The levels of vascular endothelial cell growth-related angiogenic factors and matrix metalloproteinase were also examined. DCP significantly stimulated the expression levels of epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), and matrix metalloproteinase (MMP)-2 (latent and active). Together, these data suggest that DCP is a novel type of vascular endothelial growth factor that possesses potent mitogenic and migrative activities in angiogenesis of HCC.

Des-gamma-carboxy prothrombin increases the expression of angiogenic factors in human hepatocellular carcinoma cells

AIMS

Des-gamma-carboxyl prothrombin (DCP) is a serum protein produced by hepatocellular carcinoma (HCC) cells. The aim of this study was to evaluate the angiogenic activity of DCP in HCC cells.

MAIN METHODS

The proliferation of HCC cells was measured by 3-[4, 5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) assay. The growth of HCC cells was also evaluated in vivo by using the xenografts in nude mice. The enzyme-linked immunosorbent assay (ELISA) was employed to measure the levels of angiogenic factors in supernatant of cell culture. The expression of angiogenic factors was examined by Western blot analysis and immunohistochemical staining.

KEY FINDINGS

DCP displayed the stimulation of HCC cell growth in a dose (5-80 ng/ml) and time (24-96 h) dependent manner. The increase of cell growth was also observed in nude mice bearing well-established, palpable HepG2 and SMMC-7721 xenografts after 2 weeks administration of DCP. HCC cell growth was accompanied by the elevated levels of angiogenic factors. The levels of vascular endothelial growth factor (VEGF), transforming growth factor-alpha (TGF-alpha) and basic fibroblast growth factor (bFGF) in supernatant of SMMC-7721 cells were increased from 47, 126, and 60 pg/10(6) cells/24 h to 400, 208, and 298 pg/10(6) cells/24 h, respectively, after 72 h incubation with 80 ng/ml of DCP. The results of Western blot analysis and immunohistochemical staining of HCC xenografts also showed the significant increase of VEGF, TGF-alpha, and bFGF in HCC cells.

SIGNIFICANCE

These results provide the information that DCP is a type of growth factor in progression of HCC.

Des-gamma-carboxy prothrombin as an important prognostic indicator in patients with small hepatocellular carcinoma

AIM: To clarify the effect of a high des-gamma-carboxy prothrombin (DCP) level on the invasiveness and prognosis of small hepatocellular carcinoma.

METHODS: Among 142 consecutive patients with known DCP levels, who underwent hepatectomy because of hepatocellular carcinoma, 85 patients met the criteria for small hepatocellular carcinoma, i.e. one ≤ 5 cm sized single tumor or no more than three ≤ 3 cm sized tumors.

RESULTS: The overall survival rate of the 142 patients was 92.1% for 1 year, 69.6% for 3 years, and 56.9% for 5 years. Multivariate analysis showed that microscopic vascular invasion (P = 0.03) and serum DCP ≥ 400 mAU/mL (P = 0.02) were independent prognostic factors. In the group of patients who met the criteria for small hepatocellular carcinoma, DCP ≥ 400 mAU/mL was found to be an independent prognostic factor for recurrence-free (P = 0.02) and overall survival (P = 0.0005). In patients who did not meet the criteria, the presence of vascular invasion was an independent factor for recurrence-free (P = 0.02) and overall survivals (P = 0.01). In 75% of patients with small hepatocellular carcinoma and high DCP levels, recurrence occurred extrahepatically.

CONCLUSION: For small hepatocellular carcinoma, a high preoperative DCP level appears indicative for tumor recurrence. Because many patients with a high preoperative DCP level develop extrahepatic recurrence, it is necessary to screen the whole body.

Combining multiple microarrays in the presence of controlling variables

MOTIVATION

Microarray technology enables the monitoring of expression levels for thousands of genes simultaneously. When the magnitude of the experiment increases, it becomes common to use the same type of microarrays from different laboratories or hospitals. Thus, it is important to analyze microarray data together to derive a combined conclusion after accounting for the differences. One of the main objectives of the microarray experiment is to identify differentially expressed genes among the different experimental groups. The analysis of variance (ANOVA) model has been commonly used to detect differentially expressed genes after accounting for the sources of variation commonly observed in the microarray experiment.

RESULTS

We extended the usual ANOVA model to account for an additional variability resulting from many confounding variables such as the effect of different hospitals. The proposed model is a two-stage ANOVA model. The first stage is the adjustment for the effects of no interests. The second stage is the detection of differentially expressed genes among the experimental groups using the residuals obtained from the first stage. Based on these residuals, we propose a permutation test to detect the differentially expressed genes. The proposed model is illustrated using the data from 133 microarrays collected at three different hospitals. The proposed approach is more flexible to use, and it is easier to accommodate the individual covariates in this model than using the meta-analysis approach.

AVAILABILITY

A set of programs written in R will be electronically sent upon request.

Distribution of the heterogeneity of des-gamma-carboxyprothrombin in patients with hepatocellular carcinoma

BACKGROUND AND AIM

Our aim was to evaluate the heterogeneity of des-gamma-carboxyprothrombin (DCP) in the plasma of patients with hepatocellular carcinoma (HCC), benign liver diseases, and normal controls and compare the DCP values by enzyme-linked immunosorbent assay (ELISA) for two types monoclonal antibodies (MU-3 and 19B7).

METHODS

We purified DCP from the plasma of 17 patients with HCC, three patients with metastatic liver tumors (MTLT), 12 with acute hepatitis (AH), five with chronic hepatitis (CH), nine with liver cirrhosis (LC), and 10 normal controls (NC). The DCP was analyzed by using immunoaffinity chromatography, reversed-phase high-performance liquid chromatography and measured by using an ELISA.

RESULTS

In HCC, the synthesis of the 1-, 3-, and 4-Gla (gamma-carboxyglutamic acid) DCP variants markedly increased, and those levels accounted for more than 50% of the DCP. The synthesis of the 3-, and 4-Gla DCP gradually increased in order of AH, CH, and LC patients. The MU-3 antibody reacted with the 1-, 3- and 4-Gla DCP variants, whereas the 19B7 antibody reacted with the 6-, 7- and 8-Gla variants. The DCP was measured by ELISA, markedly increased in order of NC, AH, CH, LC, and HCC cases. The correlation of the ratios (1 + 3 + 4)-Gla/(6 + 7 + 8)-Gla DCP and MU-3/19B7 was positive and statistically significant (r = 0.786, n = 56).

CONCLUSIONS

According to the severity of liver damages, the synthesis of the 1-, 3- and 4-Gla DCP variants that lost the Ca binding from the outside of the Gla-domain of the prothrombin molecule increases and the MU-3/19B7 ratio is believed to reflect this.