Non-endothelial KDR/flk-1 expression is associated with increased survival of patients with urothelial bladder carcinomas

Clinicopathological and Prognostic Value of Ki-67 Expression in Bladder Cancer: A Systematic Review and Meta-Analysis

Background

Ki-67 is an established marker of cell proliferation, and the Ki-67 index correlates with the clinical course of several cancer types, including bladder cancer (BC). However, the clinicopathological and prognostic significance of Ki-67 in bladder cancer remains unclear. Therefore, we performed a systematic review and meta-analysis to clarify this relationship.

Methods

A comprehensive literature search for relevant studies published up to February 1, 2016, was performed using PubMed, Cochrane Library, Embase and ISI Web of Knowledge. The effects of Ki-67 expression on survival outcome in patients with BC and BC subtypes were evaluated. Furthermore, the relationship between Ki-67 expression and the clinicopathological features of BC were assessed.

Results

Thirty-one studies with 5147 bladder cancer patients were selected for evaluation. Ki-67 expression was significantly associated with shorter recurrence-free (HR 1.69, 95% CI: 1.33–2.14), progression-free (HR 1.89, 95% CI: 1.43–2.51), overall (HR 2.03, 95% CI: 1.31–3.16), and cancer-specific (HR 1.69, 95% CI: 1.47–1.95) survival. Moreover, whereas high expression was more common in high tumor stage, recurrence status, tumor size, there was no correlation between high Ki-67 expression and age, gender, smoking habits, and tumor number. Importantly, analysis of the different subgroups of BC suggested that significant correlations between high Ki-67 expression and survival outcome (recurrence-free/progression-free/overall/cancer-specific survival) are present only in European-American patients.

Conclusion

The present results indicate that over-expression of Ki-67 is distinctly correlated with poor patient survival. Ki-67 may serve as a valuable biomarker for prognosis in BC patients, particularly in non-Asian BC patients. The results suggest no significant association between Ki-67 expression and BC prognosis in Asian patients. Further efforts are needed to fully clarify this relationship.

High Ki-67 Immunohistochemical Reactivity Correlates With Poor Prognosis in Bladder Carcinoma: A Comprehensive Meta-Analysis with 13,053 Patients Involved

Ki-67 is considered as one of prime biomarkers to reflect cell proliferation and immunohistochemical Ki-67 staining has been widely applied in clinical pathology. To solve the widespread controversy whether Ki-67 reactivity significantly predicts clinical prognosis of bladder carcinoma (BC), we performed a comprehensive meta-analysis by combining results from different literature. A comprehensive search was conducted in the Chinese databases of WanFang, China National Knowledge Infrastructure and Chinese VIP as well as English databases of PubMed, ISI web of science, EMBASE, Science Direct, and Wiley online library. Independent studies linking Ki-67 to cancer-specific survival (CSS), disease-free survival (DFS), overall survival (OS), progression-free survival (PFS), and recurrence-free survival (RFS) were included in our meta-analysis. With the cut-off values literature provided, hazard ratio (HR) values between the survival distributions were extracted and later combined with STATA 12.0. In total, 76 studies (n = 13,053 patients) were eligible for the meta-analysis. It was indicated in either univariate or multivariate analysis for survival that high Ki-67 reactivity significantly predicted poor prognosis. In the univariate analysis, the combined HR for CSS, DFS, OS, PFS, and RFS were 2.588 (95% confidence interval [CI]: 1.623-4.127, P < 0.001), 2.697 (95%CI: 1.874-3.883, P < 0.001), 2.649 (95%CI: 1.632-4.300, P < 0.001), 3.506 (95%CI: 2.231-5.508, P < 0.001), and 1.792 (95%CI: 1.409-2.279, P < 0.001), respectively. The pooled HR of multivariate analysis for CSS, DFS, OS, PFS, and RFS were 1.868 (95%CI: 1.343-2.597, P < 0.001), 2.626 (95%CI: 2.089-3.301, P < 0.001), 1.104 (95%CI: 1.008-1.209, P = 0.032), 1.518 (95%CI: 1.299-1.773, P < 0.001), and 1.294 (95%CI: 1.203-1.392, P < 0.001), respectively. Subgroup analysis of univariate analysis by origin showed that Ki-67 reactivity significantly correlated with all 5 clinical outcome in Asian and European-American patients (P < 0.05). For multivariate analysis, however, the pooled results were only significant for DFS, OS, and RFS in Asian patients, for CSS, DFS, PFS, and RFS in European-American patients (P < 0.05). In the subgroup with low cut-off value (<20%), our meta-analysis indicated that high Ki-67 reactivity was significantly correlated with worsened CSS, DFS, OS, PFS, and RFS on univariate analysis (P < 0.05). For multivariate analysis, the meta-analysis of literature with low cut-off value (<20%) demonstrated that high Ki-67 reactivity predicted shorter DFS, PFS, and RFS in BC patients (P < 0.05). In the subgroup analysis of high cut-off value (≥20%), our meta-analysis indicated that high Ki-67 reactivity, in either univariate or multivariate analysis, significantly correlated with all five clinical outcomes in BC patients (P < 0.05). The meta-analysis indicates that high Ki-67 reactivity significantly correlates with deteriorated clinical outcomes in BC patients and that Ki-67 can be considered as an independent indicator for the prognosis by the meta-analyses of multivariate analysis.

Vascular endothelial growth factor receptor 2, but not S100A4 or S100A6, correlates with prolonged survival in advanced urothelial carcinoma

OBJECTIVE

A major challenge in muscle-invasive urothelial carcinoma (UC) is to identify biomarkers that can predict disease prognosis and treatment response after cystectomy. Therefore, we analyzed the potential prognostic value of the proteins vascular endothelial growth factor receptor 2 (VEGFR2), S100A4, and S100A6 in UC.

METHODS

Retrospective outcome data and tumor specimens from 83 cystectomy patients with histologically confirmed invasive UC were included. Expression levels of VEGFR2 (also called flk-1 and KDR), S100A4, and S100A6 were analyzed in primary tumor tissue by immunohistochemistry.

RESULTS

Immunohistochemical staining and analysis of VEGFR2, S100A4, and S100A6 showed localization mainly in tumor cell cytoplasm. High VEGFR2 expression and low tumor category were independent variables associated with longer overall survival (OS) and disease-free survival, revealed by a bivariate Cox proportional hazards regression model (both P<0.001). In addition, the univariate log-rank test and the Cox model demonstrated that OS beyond 2 years was significantly greater among patients with low S100A6 expression than in those with high S100A6 expression (P = 0.017 and 0.022, respectively). Differences in tumor expression of S100A4 were not significantly associated with outcome.

CONCLUSION

In this study, VEGFR2 expression was significantly correlated with risk of disease relapse and OS in a defined cohort of patients with UC of the bladder treated by cystectomy.

The use of genetic programming in the analysis of quantitative gene expression profiles for identification of nodal status in bladder cancer

Background

Previous studies on bladder cancer have shown nodal involvement to be an independent indicator of prognosis and survival. This study aimed at developing an objective method for detection of nodal metastasis from molecular profiles of primary urothelial carcinoma tissues.

Methods

The study included primary bladder tumor tissues from 60 patients across different stages and 5 control tissues of normal urothelium. The entire cohort was divided into training and validation sets comprised of node positive and node negative subjects. Quantitative expression profiling was performed for a panel of 70 genes using standardized competitive RT-PCR and the expression values of the training set samples were run through an iterative machine learning process called genetic programming that employed an N-fold cross validation technique to generate classifier rules of limited complexity. These were then used in a voting algorithm to classify the validation set samples into those associated with or without nodal metastasis.

Results

The generated classifier rules using 70 genes demonstrated 81% accuracy on the validation set when compared to the pathological nodal status. The rules showed a strong predilection for ICAM1, MAP2K6 and KDR resulting in gene expression motifs that cumulatively suggested a pattern ICAM1>MAP2K6>KDR for node positive cases. Additionally, the motifs showed CDK8 to be lower relative to ICAM1, and ANXA5 to be relatively high by itself in node positive tumors. Rules generated using only ICAM1, MAP2K6 and KDR were comparably robust, with a single representative rule producing an accuracy of 90% when used by itself on the validation set, suggesting a crucial role for these genes in nodal metastasis.

Conclusion

Our study demonstrates the use of standardized quantitative gene expression values from primary bladder tumor tissues as inputs in a genetic programming system to generate classifier rules for determining the nodal status. Our method also suggests the involvement of ICAM1, MAP2K6, KDR, CDK8 and ANXA5 in unique mathematical combinations in the progression towards nodal positivity. Further studies are needed to identify more class-specific signatures and confirm the role of these genes in the evolution of nodal metastasis in bladder cancer.

The vascular-targeting fusion toxin VEGF121/rGel inhibits the growth of orthotopic human bladder carcinoma tumors

Vascular endothelial growth factor (VEGF) and its receptors (FLT-1 and KDR) are overexpressed by human bladder cancer cells and tumor endothelial cells, respectively. Strategies that target VEGF receptors hold promise as antiangiogenic therapeutic approaches to bladder cancer. A fusion protein of VEGF121 and the plant toxin gelonin (rGel) was constructed, expressed in bacteria, and purified to homogeneity. Cytotoxicity experiments of VEGF121/rGel on the highly metastatic 253J B-V human bladder cancer cell line demonstrated that the VEGF121/rGel does not specifically target these cells, whereas Western blot analysis showed no detectable expression of KDR. Treatment with VEGF121/rGel against orthotopically implanted 253J B-V xenografts in nude mice resulted in a significant suppression of bladder tumor growth (approximately 60% inhibition; P < .05) compared to controls. Immunohistochemistry studies of orthotopic 253J B-V tumors demonstrated that KDR is highly overexpressed in tumor vasculature. Immunofluorescence staining with antibodies to CD-31 (blood vessel endothelium) and rGel demonstrated a dramatic colocalization of the construct on tumor neovasculature. Treated tumors also displayed an increase in terminal deoxynucleotidyl transferase-mediated dUTP-biotin end labeling staining compared to controls. Thus, VEGF121/rGel inhibits the growth of human bladder cancer by cytotoxic effects directed against the tumor vascular supply and has significant potential as a novel antiangiogenic therapeutic against human bladder cancer.

Identification of H-2Db-Specific CD8+ T-Cell Epitopes From Mouse VEGFR2 That Can Inhibit Angiogenesis and Tumor Growth

Vascular endothelial growth factor receptor 2 (VEGFR2/KDR) plays a crucial role in tumor-associated angiogenesis and vascularization. It has been established that monoclonal antibodies against VEGFR2 can inhibit angiogenesis. In this study, two naturally processed CD8 T-cell epitopes (VILTNPISM and FSNSTNDILI) were identified from murine KDR. Cytotoxic T lymphocytes targeting endothelial cells could be directly monitored by KDR2 and KDR3 Elispots or major histocompatibility complex class I tetramer staining. Immunization with these two peptides effectively reduced angiogenesis and inhibited tumor growth in mouse models. Thus, vaccination with KDR peptides alone or in combination with other anti-angiogenesis agents may afford a novel immunotherapy for inhibition of tumor growth.