Dickkopf-1: As a Diagnostic and Prognostic Serum Marker for Early Hepatocellular Carcinoma

DKK1-CKAP4 signal axis promotes hepatocellular carcinoma aggressiveness

Hepatocellular carcinoma (HCC) is the most prevalent malignant liver neoplasm. Despite the advances in diagnosis and treatment, the prognosis of HCC patients remains poor. Cytoskeleton-associated membrane protein 4 (CKAP4) is a receptor of the glycosylated secretory protein Dickkopf-1 (DKK1), and the DKK1-CKAP4 axis is activated in pancreatic, lung, and esophageal cancer cells. Expression of DKK1 and CKAP4 has been examined in HCC in independent studies that yielded contradictory results. In this study, the relationship between the DKK1-CKAP4 axis and HCC was comprehensively examined. In 412 HCC cases, patients whose tumors were positive for both DKK1 and CKAP4 had a poor prognosis compared to those who were positive for only one of these markers or negative for both. Deletion of either DKK1 or CKAP4 inhibited HCC cell growth. In contrast to WT DKK1, DKK1 lacking the CKAP4 binding region did not rescue the phenotypes caused by DKK1 depletion, suggesting that binding of DKK1 to CKAP4 is required for HCC cell proliferation. Anti-CKAP4 Ab inhibited HCC growth, and its antitumor effect was clearly enhanced when combined with lenvatinib, a multikinase inhibitor. These results indicate that simultaneous expression of DKK1 and CKAP4 is involved in the aggressiveness of HCC, and that the combination of anti-CKAP4 Ab and other therapeutics including lenvatinib could represent a promising strategy for treating advanced HCC.

Dickkopf-1 Promotes Angiogenesis and is a Biomarker for Hepatic Stem Cell-like Hepatocellular Carcinoma

Cancer stemness evinces interest owing to the resulting malignancy and poor prognosis. We previously demonstrated that hepatic stem cell-like hepatocellular carcinoma (HpSC-HCC) is associated with high vascular invasion and poor prognosis. Dickkopf-1 (DKK-1), a Wnt signaling regulator, is highly expressed in HpSC-HCC. Here, we assessed the diagnostic and prognostic potential of serum DKK-1. Its levels were significantly higher in 391 patients with HCC compared with 205 patients with chronic liver disease. Receiver operating characteristic curve analysis revealed the optimal cutoff value of DKK-1 to diagnose HCC and predict the 3-year survival as 262.2 and 365.9 pg/mL, respectively. HCC patients with high-serum DKK-1 levels showed poor prognosis. We evaluated the effects of anti-DKK-1 antibody treatment on tumor growth in vivo and of recombinant DKK-1 on cell proliferation, invasion, and angiogenesis in vitro. DKK-1 knockdown decreased cancer cell proliferation, migration, and invasion. DKK-1 supplementation promoted angiogenesis in vitro; this effect was abolished by an anti-DKK-1 antibody. Co-injection of the anti-DKK-1 antibody with Huh7 cells inhibited their growth in NOD/SCID mice. Thus, DKK-1 promotes proliferation, migration, and invasion of HCC cells and activates angiogenesis in vascular endothelial cells. DKK-1 is a prognostic biomarker for HCC and a functional molecule for targeted therapy.

Dickkopf Proteins and Their Role in Cancer: A Family of Wnt Antagonists with a Dual Role

The Wnt signaling pathway regulates crucial aspects such as cell fate determination, cell polarity and organogenesis during embryonic development. Wnt pathway deregulation is a hallmark of several cancers such as lung, gastric and liver cancer, and has been reported to be altered in others. Despite the general agreement reached by the scientific community on the oncogenic potential of the central components of the pathway, the role of the antagonist proteins remains less clear. Deregulation of the pathway may be caused by overexpression or downregulation of a wide range of antagonist proteins. Although there is growing information related to function and regulation of Dickkopf (DKK) proteins, their pharmacological potential as cancer therapeutics still has not been fully developed. This review provides an update on the role of DKK proteins in cancer and possible potential as therapeutic targets for the treatment of cancer; available compounds in pre-clinical or clinical trials are also reviewed.

Serum epidermal growth factor-like domain 7 serves as a novel diagnostic marker for early hepatocellular carcinoma

Background

Epidermal growth factor-like domain 7 (Egfl7), a recently identified secreted protein, was significantly increased in patients with HCC by our previous studies. However, its efficacy in the diagnosis of early HCC remains unknown. In this study, we therefore evaluate the efficacy of serum Egfl7 for early HCC diagnosis and compare it with alpha-fetoprotein (AFP).

Methods

Serum Egfl7 levels in testing cohort (1081 participants) and validation cohort (476 participants) were measured by a sandwich enzyme-linked immunoassay (ELISA). The cut-off value of Egfl7 was determined by Youden’s index and the efficacies of Egfl7 and AFP in diagnosing early HCC were estimated by receiver operating characteristic (ROC).

Results

Serum Egfl7 was significantly elevated in patients with early HCC than all non-HCC controls in whatever Testing Cohort or Validation Cohort. In the Testing Cohort, ROC curves showed the optimum cut-off value of Egfl7 was 2610 ng/mL and Egfl7 showed a significantly higher sensitivity than AFP in discriminating early HCC from healthy individuals (77.4% vs. 65.3%, P = 0.0013) but the area under ROC (AUROC) and accuracy of Egfl7 and AFP were similar (0.860 vs. 0.868, P = 0.704; 80.2% vs. 83.8%, P = 0.184). In distinguishing patients with early HCC from patients with chronic liver disease (CLD), the AUROC, sensitivity, specificity and accuracy of Egfl7 were 0.800, 75.2, 71.7 and 73.5%, which were all significantly higher than AFP (0.675, 61.8, 62.0 and 61.9% in order). Egfl7 also showed a significant higher sensitivity and accuracy than AFP (76.6% vs. 64.0%, P = 0.0031; 79.9% vs. 66.1%, P < 0.0001) in differentiating early HCC patients from non-HCC individuals. Additionally, 70.8% of early HCC patients with negative AFP could be diagnosed by Egfl7 and the combined use of Egfl7 and AFP increased the sensitivity to 91.0%. These results were confirmed by a validation cohort.

Conclusion

Egfl7 is a valuable serum marker in the diagnosis of early HCC and could complement the efficacy of AFP, especially in distinguishing early HCC from CLD and identifying patients with AFP-negative early HCC.

Abdominal ultrasound and alpha-foetoprotein for the diagnosis of hepatocellular carcinoma in adults with chronic liver disease

BACKGROUND

Hepatocellular carcinoma (HCC) occurs mostly in people with chronic liver disease and ranks sixth in terms of global instances of cancer, and fourth in terms of cancer deaths for men. Despite that abdominal ultrasound (US) is used as an initial test to exclude the presence of focal liver lesions and serum alpha-foetoprotein (AFP) measurement may raise suspicion of HCC occurrence, further testing to confirm diagnosis as well as staging of HCC is required. Current guidelines recommend surveillance programme using US, with or without AFP, to detect HCC in high-risk populations despite the lack of clear benefits on overall survival. Assessing the diagnostic accuracy of US and AFP may clarify whether the absence of benefit in surveillance programmes could be related to under-diagnosis. Therefore, assessment of the accuracy of these two tests for diagnosing HCC in people with chronic liver disease, not included in surveillance programmes, is needed.

OBJECTIVES

Primary: the diagnostic accuracy of US and AFP, alone or in combination, for the diagnosis of HCC of any size and at any stage in adults with chronic liver disease, either in a surveillance programme or in a clinical setting. Secondary: to assess the diagnostic accuracy of abdominal US and AFP, alone or in combination, for the diagnosis of resectable HCC; to compare the diagnostic accuracy of the individual tests versus the combination of both tests; to investigate sources of heterogeneity in the results.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Hepato-Biliary Group Diagnostic-Test-Accuracy Studies Register, Cochrane Library, MEDLINE, Embase, LILACS, Science Citation Index Expanded, until 5 June 2020. We applied no language or document-type restrictions.

SELECTION CRITERIA

Studies assessing the diagnostic accuracy of US and AFP, independently or in combination, for the diagnosis of HCC in adults with chronic liver disease, with cross-sectional and case-control designs, using one of the acceptable reference standards, such as pathology of the explanted liver, histology of resected or biopsied focal liver lesion, or typical characteristics on computed tomography, or magnetic resonance imaging, all with a six-months follow-up.

DATA COLLECTION AND ANALYSIS

We independently screened studies, extracted data, and assessed the risk of bias and applicability concerns, using the QUADAS-2 checklist. We presented the results of sensitivity and specificity, using paired forest-plots, and tabulated the results. We used a hierarchical meta-analysis model where appropriate. We presented uncertainty of the accuracy estimates using 95% confidence intervals (CIs). We double-checked all data extractions and analyses.

MAIN RESULTS

We included 373 studies. The index-test was AFP (326 studies, 144,570 participants); US (39 studies, 18,792 participants); and a combination of AFP and US (eight studies, 5454 participants). We judged at high-risk of bias all but one study. Most studies used different reference standards, often inappropriate to exclude the presence of the target condition, and the time-interval between the index test and the reference standard was rarely defined. Most studies with AFP had a case-control design. We also had major concerns for the applicability due to the characteristics of the participants. As the primary studies with AFP used different cut-offs, we performed a meta-analysis using the hierarchical-summary-receiver-operating-characteristic model, then we carried out two meta-analyses including only studies reporting the most used cut-offs: around 20 ng/mL or 200 ng/mL. AFP cut-off 20 ng/mL: for HCC (147 studies) sensitivity 60% (95% CI 58% to 62%), specificity 84% (95% CI 82% to 86%); for resectable HCC (six studies) sensitivity 65% (95% CI 62% to 68%), specificity 80% (95% CI 59% to 91%). AFP cut-off 200 ng/mL: for HCC (56 studies) sensitivity 36% (95% CI 31% to 41%), specificity 99% (95% CI 98% to 99%); for resectable HCC (two studies) one with sensitivity 4% (95% CI 0% to 19%), specificity 100% (95% CI 96% to 100%), and one with sensitivity 8% (95% CI 3% to 18%), specificity 100% (95% CI 97% to 100%). US: for HCC (39 studies) sensitivity 72% (95% CI 63% to 79%), specificity 94% (95% CI 91% to 96%); for resectable HCC (seven studies) sensitivity 53% (95% CI 38% to 67%), specificity 96% (95% CI 94% to 97%). Combination of AFP (cut-off of 20 ng/mL) and US: for HCC (six studies) sensitivity 96% (95% CI 88% to 98%), specificity 85% (95% CI 73% to 93%); for resectable HCC (two studies) one with sensitivity 89% (95% CI 73% to 97%), specificity of 83% (95% CI 76% to 88%), and one with sensitivity 79% (95% CI 54% to 94%), specificity 87% (95% CI 79% to 94%). The observed heterogeneity in the results remains mostly unexplained, and only in part referable to different cut-offs or settings (surveillance programme compared to clinical series). The sensitivity analyses, excluding studies published as abstracts, or with case-control design, showed no variation in the results. We compared the accuracy obtained from studies with AFP (cut-off around 20 ng/mL) and US: a direct comparison in 11 studies (6674 participants) showed a higher sensitivity of US (81%, 95% CI 66% to 90%) versus AFP (64%, 95% CI 56% to 71%) with similar specificity: US 92% (95% CI 83% to 97%) versus AFP 89% (95% CI 79% to 94%). A direct comparison of six studies (5044 participants) showed a higher sensitivity (96%, 95% CI 88% to 98%) of the combination of AFP and US versus US (76%, 95% CI 56% to 89%) with similar specificity: AFP and US 85% (95% CI 73% to 92%) versus US 93% (95% CI 80% to 98%).

AUTHORS' CONCLUSIONS

In the clinical pathway for the diagnosis of HCC in adults, AFP and US, singularly or in combination, have the role of triage-tests. We found that using AFP, with 20 ng/mL as a cut-off, about 40% of HCC occurrences would be missed, and with US alone, more than a quarter. The combination of the two tests showed the highest sensitivity and less than 5% of HCC occurrences would be missed with about 15% of false-positive results. The uncertainty resulting from the poor study quality and the heterogeneity of included studies limit our ability to confidently draw conclusions based on our results.

Lung Cancer Cells-Controlled Dkk-1 Production in Brain Metastatic Cascade Drive Microglia to Acquire a Pro-tumorigenic Phenotype

Objectives

Organotropism is primarily determined by tumor-derived exosomes. To date, the role of lung cancer cells-derived exosomes underlying the pre-metastatic niche formation is unclear.

Materials and Methods

The animal models of retro-orbital and intra-ventricular injection were constructed to administrate lung cancer cells-derived exosomes. Cytokine array was used to screen the cytokines released from brain endothelium after internalization of lung cancer cells-derived exosomes. The cellular co-culture system was established to mimic microglia-vascular niche contained lung cancer cells-derived exosomes. The levels of Dkk-1 and the activities of microglia were analyzed by qRT-PCR, western blot and immunofluorescence. In vivo selections of highly brain metastatic cells were performed to analyze the direct interaction of lung cancer cells with microglia.

Results

Animal studies demonstrated that there was a suppressive signal transferred from brain endothelium to microglia after internalization of lung cancer cells-derived exosomes into brain endothelium, which caused an absolutely less M1 phenotypic microglia and a relatively more M2 phenotypic microglia. Further results indicated that lung cancer cells-derived exosomes induced a release of endogenous Dkk-1 from brain endothelium, which rendered microglia to acquire a pro-tumorigenic feature in pre-metastatic niche. Subsequently, the declines of Dkk-1 in metastatic lung cancer cells removed the suppression on microglia and enhanced microglial activation in metastatic niche.

Conclusion

Our findings shed a new light on the synergistic reaction of the different cells in “neurovascular units” toward the metastatic messages from lung cancer cells and provided a potential therapeutic pathway for lung cancer metastasis to brain.

Diagnosis Accuracy and Prognostic Significance of the Dickkopf-1 Protein in Gastrointestinal Carcinomas: Systematic Review and Network Meta-analysis

Objective: To evaluate the diagnosis accuracy and prognostic significance of bio-marker dickkopf-1(DKK-1) protein in GIC, and also sub-type of hepatocellular carcinoma (HCC), pancreas carcinomas (PC), oesophageal carcinoma (EPC) and Adenocarcinoma of esophago-gastric junction (AEGJ), etc.

Methods: Electronic databases were searched from inception to May 2020. Patients were diagnosed with gastrointestinal carcinomas, and provided data on the correlation between high and low DKK-1 expression and diagnosis or prognosis.

Results: Forty-three publications involving 9318 participants were included in the network meta-analysis, with 31 of them providing data for diagnosis value and 18 records were eligible for providing prognosis value of DKK-1. DKK-1 has a moderate diagnostic value for overall GIC, HCC and PC. In addition, for the combined diagnosis value of DKK-1 +AFP, high diagnostic accuracy value could be determined in HCC and early HCC group, respectively. Whereas, diagnosis efficiency of DKK-1+CA19-9 was also better than that of DKK-1 alone with AUC value is above 0.95. For the prognosis meta-analysis of histopathological stratification, we found that EPC and AEGJ ranked the best for the histopathological stratification of prognosis from network meta-analysis. This systematic review protocol was registered with the PROSPERO registry (No.CRD42020167910).

Conclusion: DKK-1 has good diagnostic accuracy, especially combination of DKK-1+AFP in HCC and DKK-1+CA19-9 in PC, whereas modest prognostic significant in GIC. Future head-to-head researches are warranted for DKK-1 expression in HCC and PC tissue.

New Blood Biomarkers for the Diagnosis of AFP-Negative Hepatocellular Carcinoma

An early diagnosis of hepatocellular carcinoma (HCC) followed by effective treatment is currently critical for improving the prognosis and reducing the associated economic burden. Alpha-fetoprotein (AFP) is the most widely used biomarker for HCC diagnosis. Based on elevated serum AFP levels as well as typical imaging features, AFP-positive HCC (APHC) can be easily diagnosed, but AFP-negative HCC (ANHC) is not easily detected due to lack of ideal biomarkers and thus mainly reliance on imaging. Imaging for the diagnosis of ANHC is probably insufficient in sensitivity and/or specificity because most ANHC tumors are small and early-stage HCC, and it is involved in sophisticated techniques and high costs. Moreover, ANHC accounts for nearly half of HCC and exhibits a better prognosis compared with APHC. Therefore, the diagnosis of ANHC in clinical practice has been a critical issue for the early treatment and prognosis improvement of HCC. In recent years, tremendous efforts have been made to discover new biomarkers complementary to AFP for HCC diagnosis. In this review, we systematically review and discuss the recent advances of blood biomarkers for HCC diagnosis, including DNA biomarkers, RNA biomarkers, protein biomarkers, and conventional laboratory metrics, focusing on their diagnostic evaluation alone and in combination, in particular on their diagnostic performance for ANHC.

Study of Dickkopf-1 (DKK-1) in patients with chronic viral hepatitis C-related liver cirrhosis with and without hepatocellular carcinoma

Aim of the study

Dickkopf-1 (DKK-1) is a secreted protein which acts as an inhibitor of Wnt/β-catenin signaling. DKK-1 was found to be a helpful biomarker for many cancers including hepatocellular carcinoma (HCC). HCC is multifactorial in origin and its main etiology in Egypt is attributed to chronic hepatitis C virus (HCV) infection. Objectives: To assess the serum level and diagnostic performance of DKK-1 and α-fetoprotein (AFP) in Egyptian patients with chronic HCV-related liver cirrhosis with and without HCC.

Material and methods

80 subjects were divided into: a control group (group I, 20 healthy volunteers) and two patient groups: group II (HCV with liver cirrhosis, 30 patients), and group III, (HCV-related liver cirrhosis with HCC, 30 patients). Thorough physical examination, triphasic computed tomography, calculation of Child-Pugh score, laboratory investigations (complete blood picture, liver profile, hepatitis B surface antigen, anti-HCV antibodies, AFP (chemiluminometry) and DKK-1 (ELISA) were performed.

Results

There was a significant decrease in DKK-1 level in HCV patients with liver cirrhosis (group II) and HCV patients with HCC (group III) compared to the control group (group I) (p < 0.001). However, there was a significant increase in DKK-1 level in HCV patients with HCC (group III) compared to HCV patients with liver cirrhosis (group II) (p < 0.033). The ROC curve showed that DKK-1 has less sensitivity but higher specificity in HCV patients with HCC (group III) compared with HCV patients with liver cirrhosis (group II).

Conclusions

The combination of DKK-1 and AFP could further improve the diagnostic accuracy of HCV-related cirrhosis with or without HCC.

The anti-DKK1 antibody DKN-01 as an immunomodulatory combination partner for the treatment of cancer

INTRODUCTION

The Wnt/beta-catenin pathway is a complex signaling pathway known to be dysregulated in several cancers; Dickkopf-1 (Dkk1) is an inhibitor of canonical Wnt signaling via negative feedback. Elevated Dkk1 is associated with a poor prognosis in several cancers, including gynecologic and gastroesophageal malignancies. This review focuses on the potential therapeutic benefit of targeting Dkk1 with the IgG4 monoclonal antibody, DKN-01.

AREAS COVERED

We highlight current treatment approaches for advanced gynecologic and esophageal malignancies highlighting the need for more effective therapies, specifically improved immune-modulating agents and combinations. Our discussion of DKN-01 addresses the rationale for targeting Dkk1, available safety, pharmacokinetic and efficacy data.

EXPERT OPINION

DKN-01 presents an interesting therapeutic consideration in advanced gynecologic and gastroesophageal malignancies. It has been especially promising in patients with high-Dkk1-expressing tumors or known Wnt mutations. We postulate that the complementary mechanisms, limited adverse effects and emerging biomarker data position DKN-01 as a promising agent for combination therapy in patients with advanced malignancies. Specifically, we believe this occurs through an immuno-modulatory effect, primarily acting through the innate arm of the immune system. This highlights the possibility for addressing innate immune resistance and expanding the portion of patients who may benefit, possibly in a biomarker-selected manner.

Serum Dickopff 1 as a Novel Biomarker in Hepatocellular Carcinoma Diagnosis and Follow Up After Ablative Therapy

Background

This study aimed to evaluate the role of Dickopff 1 (DKK1) serum levels as a marker for early detection of hepatocellular carcinoma (HCC) and to compare it with alphafetoprotein (AFP) after non-surgical intervention (microwave ablation, radiofrequency ablation) in HCC.

Patients and methods

This prospective study was conducted in Al-Mahalla hepatology teaching hospital from June 2015 to June 2017. One hundred and twenty patients were included. They were classified into four groups: Group A: 40 patients with chronic liver disease; Group B: 40 patients with HCC which were divided into 2 main sub groups, group Ba which included HCC patients who were not eligible for ablative therapy and group Bb which included HCC patients who were eligible for ablative therapy; Group C: 20 healthy control subjects matched for age and sex; Group D: 20 HCC patients with negative AFP, DKK1 was done for them.

Results

There was a highly significant difference (p < 0.001) between groups regarding serum level of Dickpoff 1 with mean of 1 ng/mL in group A (cirrhotic), 2.38 ng/mL in group B (HCC), and 1.83 ng/mL in group D (AFP negative HCC) in comparison to control group C with mean of 0.54 ng/mL. There was a highly statistically significant difference (p value less =0.01) in the studied groups regarding serum Dickpoff 1 before and after intervention with a mean of 2.38 ng/mL before intervention and mean of 1.37 ng/mL after 1 month of intervention.

Conclusion

Serum Dkk-1 has higher sensitivity, specificity, and accuracy in early diagnosis of HCC than AFP.

Diagnostic accuracy of serum dickkopf-1 protein in diagnosis hepatocellular carcinoma: An updated meta-analysis

BACKGROUND

To verify the accuracy of serum dickkopf-1 protein (DKK-1) in the diagnosis of hepatocellular carcinoma (HCC) by an updated meta-analysis.

METHODS

We searched potential eligible studies in PubMed and Embase before July 8, 2018. Sensitivity (SN), specificity (SP), positive likelihood ratio (PLR), negative likelihood ratio (NLR), summary receiver operating characteristics curve (sROC), and diagnostic odds ratio (DOR) were pooled with their 95% confidence intervals CIs) using a bivariate random-effects model.

RESULTS

A total of 8 articles contained 10 studies on diagnosis of HCC with DKK-1 alone,7 articles contained 9 studies on diagnosis of HCC with a-fetoprotein (AFP) alone and 5 articles contained 7 studies on diagnosis of HCC with DKK-1 + AFP were identified. The pooled SN, SP, PLR, NLR, and DOR of DKK-1 alone, AFP alone and DKK-1 + AFP were 0.72 (95% CI: 0.70-0.75), 0.62 (95% CI:0.59-0.64) and 0.80 (95% CI:0.78-0.83), 0.86 (95% CI: 0.84-0.87), 0.82 (95% CI:0.80-0.84) and 0.87 (95% CI: 0.85-0.88), 4.91 (95% CI: 2.73-8.83), 3.60 (95% CI:2.01-6.44) and 6.18 (95% CI: 4.68-8.16), 0.32 (95% CI: 0.22-0.47), 0.49 (95% CI:0.40-0.60) and 0.20 (95% CI: 0.15-0.26), and 17.21 (95% CI: 9.10-32.57), 7.45 (95% CI:3.69-15.01) and 31.39 (95% CI: 23.59-43.20), respectively. The area under the sROC was 0.88, 0.70, and 0.92 for the 3 diagnostic methods.

CONCLUSIONS

Serum DKK-1 + AFP showed a high accuracy for diagnosis of HCC, and serum DKK-1 alone had moderate accuracy as compared to a previous meta-analysis, while AFP alone owned an unsatisfied diagnostic behavior for HCC. Due to the limitations of the current analysis, further well-designed studies are needed to confirm the diagnostic value of DKK-1 and DKK-1 + AFP in HCC diagnosis.

HCC with low- and normal-serum alpha-fetoprotein levels

A large database of 1773 HCC patients in Turkey was examined. 41.9% had alpha-fetoprotein (AFP) levels <20 IU/ml and an additional 16.123% had values between 20-100 IU/ml. This 58% of the cohort (<100 IU/ml AFP levels) was examined in detail. 66% of patients with small (<5 cm) HCCs had low AFP, compared to 49% of patients with larger (>5 cm) HCCs. The mean diameter (MTD) of larger MTD, low AFP tumors was 8.4cm. Therefore, factors other than AFP must contribute to HCC tumor growth. Larger tumors in low AFP patients had both higher platelet levels and increased PVT percent. Linear regression analysis for both MTD and multifocality showed that platelet numbers and presence of PVT were significant variables; whereas for PVT, significant variables were albumin, alkaline phosphatase and MTD. Comparisons between patients with AFP levels <20, 20-<100, 100-<1000 and >1000 IU/ml showed the most significant tumor finding was an increase in PVT percent between each group, and to a lesser extent, MTD. Thus, low- or normal-AFP HCCs constitute the majority of patients and have slightly lower MTD and much lower PVT percent than HCCs associated with elevated blood AFP levels. New, non-AFP markers are thus needed, especially for small HCCs.

Rationale for targeting the Wnt signalling modulator Dickkopf-1 for oncology

Wnt signalling is a fundamental pathway involved in embryonic development and adult tissue homeostasis. Mutations in the pathway frequently lead to developmental defects and cancer. As such, therapeutic intervention of this pathway has generated tremendous interest. Dickkopf-1 (DKK1) is a secreted inhibitor of β-catenin-dependent Wnt signalling and was originally characterized as a tumour suppressor based on the prevailing view that Wnt signalling promotes cancer pathogenesis. However, DKK1 appears to increase tumour growth and metastasis in preclinical models and its elevated expression correlates with a poor prognosis in a range of cancers, indicating that DKK1 has more complex cellular and biological functions than originally appreciated. Here, we review current evidence for the cancer-promoting activity of DKK1 and recent insights into the effects of DKK1 on signalling pathways in both cancer and immune cells. We discuss the rationale and promise of targeting DKK1 for oncology.

LINKED ARTICLES

This article is part of a themed section on WNT Signalling: Mechanisms and Therapeutic Opportunities. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.24/issuetoc.

Serum dickkopf-1 as a clinical and prognostic factor in non-small cell lung cancer patients with bone metastases

Background

The study was designed to evaluate the association between serum dickkopf-1 (DKK1) and non-small cell lung cancer (NSCLC) bone metastases.

Materials and Methods

Serum DKK1 levels were quantified in 470 NSCLC patients, 140 with osseous metastases, 178 with extraosseous metastases, and 152 with early stage in complete remission. The Receiver Operating Characteristic (ROC) curve enabled us to identify a threshold value to distinguish patients with bone metastases.

Results

Serum DKK1 levels in patients with osseous metastases were significantly higher than in the other 2 groups (P < 0.001). ROC curves showed that the optimum cutoff was 311.8 pg/ml (area under curve 0.791, 95% confidence interval 0.739–0.843, sensitivity 77.1% and specificity 71.4%). Of interest, serum DKK1 correlated with the number of bone lesions (P = 0.042) and associated with the poor survival in NSCLC patients with osseous metastases (P = 0.029).

Conclusions

Our data shows that serum DKK1 can be used for the detection of NSCLC bone metastases. More importantly this is the first report to show that serum DKK1 is a good predictor of poor prognosis in NSCLC patients with bone metastases.

Circulating sclerostin and Dickkopf-1 levels in patients with nonalcoholic fatty liver disease

There is increasing evidence for bone-liver interplay. The main aim of this study was to determine serum sclerostin and Dickkopf (DKK)-1 levels in patients with nonalcoholic fatty liver disease (NAFLD) and their association with the disease severity. Patients with biopsy-proven NAFLD, 13 with nonalcoholic simple steatosis (SS) and 14 with steatohepatitis (NASH), and 20 gender-, age-, body mass index- and waist circumference-matched controls were enrolled. Serum sclerostin, DKK-1, bone turnover markers, vitamin D, insulin and standard biochemical and hematologic parameters were measured; lumbar spinal dual-energy X-ray absorptiometry was performed. We observed that there was a progressive decline in serum sclerostin levels from the controls (76.1 ± 6.8) to SS (53.5 ± 6.4) and NASH (46.0 ± 8.1 pmol/l) patients (p = 0.009); in adjusted pairwise comparisons, sclerostin was significantly higher in the controls than in NASH patients (p = 0.012). Although serum DKK-1 did not differ between groups (p = 0.135), there was a trend toward U-shaped distribution (controls 35.8 ± 2.8; SS 27.3 ± 2.9; NASH 36.8 ± 4.4 pmol/l). Higher DKK-1 levels were independently associated with NASH. Regarding specific histological lesions, DKK-1 levels were marginally lower in NAFLD patients with lower (≤33 %) than higher (>33 %) steatosis grade (27.7 ± 3.1 and 38.8 ± 4.7 pmol/l, respectively; p = 0.049). No other significant difference was observed within histological lesions. In conclusion, serum sclerostin levels were lower in NASH patients than in controls. DKK-1 levels were independently associated with NASH in NAFLD patients. The potential importance of these findings indicates a possible bone-liver interaction and warrants further investigation.

Modulating Dickkopf-1: A Strategy to Monitor or Treat Cancer?

Dickkopf-1 (DKK1) is a secreted Wnt/β-catenin pathway antagonist involved in embryogenesis. It was first described 25 years ago for its function in head induction and limb morphogenesis. Since then, this protein has been widely studied in the context of active Wnt/β-catenin signalling during cellular differentiation and development. Dysregulation of DKK1 has been associated with bone pathologies and has now emerged as a potential biomarker of cancer progression and prognosis for several types of malignancies. Reducing the amount of circulating DKK1 may reveal a simple and efficient strategy to limit or reverse cancer growth. This review will provide an overview of the role of Dickkopf-1 in cancer and explore its potential use as a biomarker and therapeutic target.

Diagnostic Performance of Alpha-Fetoprotein, Protein Induced by Vitamin K Absence, Osteopontin, Dickkopf-1 and Its Combinations for Hepatocellular Carcinoma

BACKGROUND & AIMS

Alpha-fetoprotein (AFP) is the most widely used serum biomarker for hepatocellular carcinoma (HCC), despite its limitations. As complementary biomarkers, protein induced by vitamin K absence (PIVKA-II), osteopontin (OPN), and Dickkopf-1 (DKK-1) have been proposed. This study aimed to perform a head-to-head comparison of the diagnostic performance of AFP, PIVKA-II, OPN and DKK-1 as single or in combination to seek the best biomarker or panel, and to investigate the clinical factors affecting their performance.

METHODS

Using 401 stored plasma samples obtained from 208 HCC patients and 193 liver cirrhosis control patients, plasma AFP, PIVKA-II, OPN and DKK-1 levels were measured by ELISA, and receiver operating characteristic curve analyses were performed for each biomarker and for every combination of two to four markers.

RESULTS

Of the four biomarkers, AFP showed the highest area under the curve (0.786). The sensitivity and specificity for each single biomarker was 62% and 90.2% (AFP>20 ng/mL), 51.0% and 91.2% (PIVKA-II>10 ng/mL), 46.2% and 80.3% (OPN>100 ng/mL), and 50.0% and 80.8% (DKK-1>500 pg/mL), respectively. Among the combinations of two biomarkers, AFP>20 ng/mL or DKK-1>500 pg/mL showed the best diagnostic performance (sensitivity 78.4%, specificity 72.5%). Triple or quadruple combination did not improve the diagnostic performance further. The patient's age, etiology and tumor invasiveness of HCC affected the performance of each marker.

CONCLUSIONS

AFP was the most useful single biomarker for HCC diagnosis, and the combined measurement of AFP and DKK-1 could maximize the diagnostic yield. Clinical decision should be based on the consideration of various factors affecting the diagnostic performance of each biomarker. Efforts to seek novel HCC biomarkers should be continued.

Serum dickkopf-1 as a biomarker in screening gastrointestinal cancers: a systematic review and meta-analysis

OBJECTIVE

Despite advances in the early diagnosis of gastrointestinal (GI) cancers, these cancers are often being detected rather late in their course. Emerging published data on the accuracy of dickkopf-1 (DKK1) for diagnosing GI cancers are inconsistent. The purpose of this systematic review and meta-analysis was to evaluate the diagnostic value of DKK1 in the diagnosis of GI cancers.

METHODS

A systematic literature search of PubMed, Web of Science, Embase, Chinese National Knowledge Infrastructure, and WANFANG databases was conducted to identify the related studies published before May 1, 2015, which investigated the diagnostic value of serum DKK1 for GI cancers. The methodological quality of each study was assessed according to the Quality Assessment of Diagnostic Accuracy Studies 2 checklist. The diagnostic performance was pooled and analyzed using a bivariate model. Publication bias was evaluated with the Deeks' funnel test.

RESULTS

A total of 15 studies with 5,076 participants were finally identified for the meta-analysis. The pooled results of sensitivity (SEN), specificity (SPE), positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio for DKK1 test were 0.72 (95% confidence interval [CI]: 0.70-0.74), 0.90 (95% CI: 0.89-0.91), 7.72 (95% CI: 4.90-12.14), 0.29 (95% CI: 0.22-0.39), and 28.95 (95% CI: 16.25-51.65) for diagnosis of GI cancers, respectively. The area under the summary receiver-operating characteristic curve was 0.8901. The SEN of DKK1 in diagnosis of gastric cancer and pancreatic cancer may be higher than hepatocellular carcinoma, and the SPE in pancreatic cancer subgroup was lower than hepatocellular carcinoma and gastric cancer subgroups.

CONCLUSION

The currently available evidence suggests that serum DKK1 is a potential biomarker with high SEN and SPE for screening GI cancers. To better elucidate the usefulness of serum DKK1, further studies are needed.

Expression of serum Dickkopf-1 in gastric cancer patients

OBJECTIVE

To explore the expression and clinical significance of DKK-1 protein in patients with gastric cancers.

METHODS

Enzyme linked immuno sorbent assay was used to detect expressions of serum DKK-1 protein in 90 cases of gastric cancers, 50 cases of gastric benign disease and 40 healthy cases. The dynamic change in serum DKK-1 protein of gastric cancer patients who accepted radical operation for a month was also observed.

RESULTS

The expression of serum DKK-1 protein in gastric cancer groups was significantly higher than that in gastric benign group's (P < 0.01) and in health control (P < 0.01). Serum DKK-1 level was increased gradually along with the progress of the disease. Serum DKK-1 levels were significantly higher in patients at TNM staging III and IV than patients at TNM staging I and II. Level of serum DKK-1 was related to microvascular invasion, differentiation degree and infiltration depth. Level of serum DKK-1 was significantly reduced in patients after radical surgery (P < 0.01).

CONCLUSIONS

The expression of serum DKK-1 protein in gastric cancer patients is increased. Level of serum DKK-1 is related to TNM staging, microvascular invasion, differentiation degree and infiltration depth. DKK-1 detection can be used as a reference index in monitoring gastric cancer progress and biological behavior.

High level of serum protein DKK1 predicts poor prognosis for patients with hepatocellular carcinoma after hepatectomy

Aim

To evaluate prognostic significance of DKK1 for hepatocelluar carcinoma.

Materials & methods

We enrolled a test cohort consisting of 266 hepatitis virus B-related hepatocelluar carcinoma patients who had undergone hepatectomy and a validation cohort of 95. Associations of DKK1 with overall survival and time to recurrence were determined by Cox proportional hazards regression model.

Results

High levels of preoperative serum DKK1 were associated with poor overall survival and higher recurrence rate and DKK1 was an independent prognostic predictor. Moreover, DKK1 maintained ability to predict recurrence for patients with low recurrence risk. Double positives of DKK1 and AFP indicated the worst overall survival and the highest recurrence rate compared with either used alone. Patients with preoperatively and 1-day postoperatively positive DKK1 had higher recurrence rates than those whose values were both negative. Similar results were found in the validation cohort.

Conclusion

Serum DKK1 could predict prognosis of hepatocelluar carcinoma after hepatectomy.

Sensitivity and specificity of Dickkopf-1 protein in serum for diagnosing hepatocellular carcinoma: a meta-analysis

OBJECTIVE

This meta-analysis evaluated the diagnostic accuracy of positive serum Dickkopf-1 (DKK1) for diagnosing hepatocellular carcinoma (HCC).

MATERIAL AND METHODS

Articles listed on Embase, PubMed, Wanfang, Weipu Periodical Database or the Chinese National Knowledge Infrastructure (CNKI) and published up to July 10, 2013, were searched in either English or Chinese. The pooled sensitivity (SEN), specificity (SPE), positive and negative likelihood ratios (PLR and NLR), diagnostic odds ratio (DOR) and summary receiver operating characteristic (sROC) curve were calculated to summarize the overall test performance.

RESULTS

Four articles (6 studies) provided DKK1 diagnostic data. The pooled SEN, SPE, PLR, NLR, DOR and area under the sROC curve of DKK1 for the diagnosis of HCC were 0.65 (95% confidence interval [95% CI], 0.52-0.76), 0.94 (95% CI, 0.82-0.98), 10.1 (95% CI, 3.68-27.74), 0.38 (95% CI, 0.28-0.51), 26.90 (95% CI, 10.45-69.19) and 0.84 (95% CI, 0.81-0.87), respectively. Three articles (5 studies) provided DKK1 and α-fetoprotein (AFP) combined test data. The pooled SEN, SPE, PLR, NLR, DOR and area under the sROC curve of combined detection for the diagnosis of HCC were 0.81 (95% CI, 0.76-0.85), 0.85 (95% CI, 0.78-0.91), 5.52 (95% CI, 3.76-8.10), 0.22 (95% CI, 0.19-0.27), 24.60 (95% CI, 17.69-34.19) and 0.88 (95% CI, 0.85-0.91), respectively.

CONCLUSION

Both DKK1 and DKK1 plus AFP had high diagnostic accuracy for diagnosis of HCC.

Identification of biomarkers for hepatocellular carcinoma by semiquantitative immunocytochemistry

AIM: To investigate the expression of key biomarkers in hepatoma cell lines, tumor cells from patients’ blood samples, and tumor tissues.

METHODS: We performed the biomarker tests in two steps. First, cells plated on coverslips were used to assess biomarkers, and fluorescence intensities were calculated using the NIH Image J software. The measured values were analyzed using the SPSS 19.0 software to make comparisons among eight cell lines. Second, eighty-four individual samples were used to assess the biomarkers’ expression. Negative enrichment of the blood samples was performed, and karyocytes were isolated and dropped onto pre-treated glass slides for further analysis by immunofluorescence staining. Fluorescence intensities were compared among hepatocellular carcinoma (HCC) patients, chronic HBV-infected patients, and healthy controls following methods similar to those used for cell lines. The relationships between the expression of biomarkers and clinical pathological parameters were analyzed by Spearman rank correlation tests. In addition, we studied the distinct biomarkers’ expression with three-dimensional laser confocal microscopy reconstructions, and Kaplan-Meier survival analysis was performed to understand the clinical significance of these biomarkers.

RESULTS: Microscopic examination and fluorescence intensity calculations indicated that cytokeratin 8/18/19 (CK) expression was significantly higher in six of the seven HCC cell lines examined than in the control cells, and the expression levels of asialoglycoprotein receptor (ASGPR) and glypican-3 (GPC3) were higher in all seven HCC cell lines than in the control. Cells obtained from HCC patients’ blood samples also displayed significantly higher expression levels of ASGPR, GPC3, and CK than cells from chronic HBV-infected patients or healthy controls; these proteins may be valuable surface biomarkers for identifying HCC circulating tumor cells isolated and enriched from the blood samples. The stem cell-like and epithelial-mesenchymal transition-related biomarkers could be detected on the karyocyte slides. ASGPR and GPC3 were expressed at high levels, and thus three-dimensional reconstructions were used to observe their expression in detail. This analysis indicated that GPC3 was localized in the cytoplasm and membrane, but that ASGPR had a polar localization. Survival analyses showed that expression of GPC3 and ASGPR is associated with a patient’s overall survival (OS).

CONCLUSION: ASGPR, GPC3, and CK may be valuable HCC biomarkers for CTC detection; the expression of ASGPR and GPC3 might be helpful for understanding patients’ OS.

Serum level of DKK-1 and its prognostic potential in non-small cell lung cancer

Background

The aim of the present study was to measure the serum level of dickkopf-1(DKK-1) in patients with non-small cell lung cancer (NSCLC), and to determine the prognostic potential of serum DKK-1 in NSCLC.

Material and methods

The present study included a total of 150 patients with NSCLC and 150 healthy controls. Serum level of DKK-1 was measured by enzyme-linked immunosorbent assay (ELISA). Numerical variables were recorded as means ± standard deviation (SD) and analyzed by independent t-tests. Categorical variables were presented as rates and analyzed by using the chi-square test or Fisher’s exact test. The overall survival was analyzed by log-rank test, and survival curves were plotted according to Kaplan–Meier.

Results

We found that serum DKK-1 level was significantly higher in patients with NSCLC than healthy controls. Mean serum DKK-1 level was 31.42 ± 6.32 ng/ml in the NSCLC group and 14.12 ± 3.29 ng/ml in the healthy control group (p <0.01). Serum DKK-1 level expression level was significantly positively correlated with TNM stage (p = 0.009), lymph node involvement(p = 0.001), and distant metastases(p < 0.001).

In the multivariate Cox proportional hazards analysis, high DKK-1 expression was independently associated with poor survival (P < 0.001; HR = 3.98; 95% CI =2.19-4.83).

Conclusions

In conclusion, our results showed that DKK-1 was overexpressed in NSCLC, and DKK-1 in serum was a good predictor of poor prognosis in patients with NSCLC. More researches are needed in the future to clarify the detailed mechanism of DKK-1 in the carcinogenesis and metastasis of NSCLC.

Virtual slides

The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1471414150119415.

A review on the diagnosis and treatment of hepatocellular carcinoma with a focus on the role of Wnts and the dickkopf family of Wnt inhibitors

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers worldwide. There are multiple etiologic factors including viral and environmental influences that can lead to HCC. Successful screening for early HCC is challenging due to the lack of well characterized and specific biomarkers. However, achieving successful screening is critically important as early diagnosis can potentially provide curative opportunities. Once HCC is advanced, there are multiple therapeutic venues, but most eventually fail, therefore developing new targeted therapies may provide greater chance for effective therapies. Along these lines, the Wnt pathway has been identified as contributing to the development and progression of HCC. Wnts can modify HCC growth and invasive ability. A key factor in the Wnt pathway is the dickkopf (DKK) family of Wnt inhibitors. DKKs have also been shown to modulate HCC progression. Additionally, several studies have suggested that DKK expression in tissue and serum has diagnostic and prognostic value.

Prognostic significance of dickkopf-1 overexpression in solid tumors: a meta-analysis

The prognostic significance of dickkopf-1 (DKK1) overexpression in solid tumors remains inconclusive. We performed a meta-analysis to evaluate the impact of DKK1 overexpression in solid tumors on patients' overall survival (OS) and disease-free survival (DFS). The pooled hazard ratio (HR) with 95 % confidence interval (CI) was used to estimate the effects. Thirteen studies were included for meta-analysis; four that evaluated hepatocellular carcinoma (HCC), two each that evaluated ovarian carcinoma, esophageal carcinoma, and lung cancer, and one each that evaluated other cancers, namely gastric cancer, breast cancer, urothelial carcinoma, and colorectal cancer. Twelve studies were evaluable for OS and six for DFS. Our analysis results indicated that DKK1 overexpression predicted poor OS (HR = 1.68, 95% CI 1.36-2.08; P < 0.001) and DFS (HR = 1.65, 95% CI 1.37-1.99; P < 0.001). Subgroup analyses showed that DKK1 overexpression was significantly related with poor OS in HCC patients (HR = 1.65; P < 0.001), ovarian carcinoma patients (HR = 2.63; P = 0.045), and other cancers patients (HR = 1.51; P = 0.021). Further, DKK1 overexpression was significantly related with poor DFS in HCC patients (HR = 1.53; P < 0.001) and other cancers patients (HR = 2.02; P < 0.001). This meta-analysis showed that DKK1 may be a novel prognostic marker in solid tumors in Asian patients; it could potentially help to further stratify patients for clinical treatment. More, well-designed studies from Western countries are needed to confirm this finding.

Secretome and degradome profiling shows that Kallikrein-related peptidases 4, 5, 6, and 7 induce TGFβ-1 signaling in ovarian cancer cells

Kallikrein‐related peptidases, in particular KLK4, 5, 6 and 7 (4–7), often have elevated expression levels in ovarian cancer. In OV‐MZ‐6 ovarian cancer cells, combined expression of KLK4–7 reduces cell adhesion and increases cell invasion and resistance to paclitaxel. The present work investigates how KLK4–7 shape the secreted proteome (“secretome”) and proteolytic profile (“degradome”) of ovarian cancer cells. The secretome comparison consistently identified >900 proteins in three replicate analyses. Expression of KLK4–7 predominantly affected the abundance of proteins involved in cell–cell communication. Among others, this includes increased levels of transforming growth factor β‐1 (TGFβ‐1). KLK4–7 co‐transfected OV‐MZ‐6 cells share prominent features of elevated TGFβ‐1 signaling, including increased abundance of neural cell adhesion molecule L1 (L1CAM). Augmented levels of TGFβ‐1 and L1CAM upon expression of KLK4–7 were corroborated in vivo by an ovarian cancer xenograft model. The degradomic analysis showed that KLK4–7 expression mostly affected cleavage sites C‐terminal to arginine, corresponding to the preference of kallikreins 4, 5 and 6. Putative kallikrein substrates include chemokines, such as growth differentiation factor 15 (GDF 15) and macrophage migration inhibitory factor (MIF). Proteolytic maturation of TGFβ‐1 was also elevated. KLK4–7 have a pronounced, yet non‐degrading impact on the secreted proteome, with a strong association between these proteases and TGFβ‐1 signaling in tumor biology.

Expression of KLK4, 5, 6, and 7 yields subtle secretome and degradome alterations.

Pro‐ and anti‐tumorigenic proteins are affected.

TGFβ‐1 signaling is elevated.

Degradomic analysis supports cell‐contextual KLK activity.

Potential substrates of KLK4–7 have been identified.