The vascular delta-like ligand-4 (DLL4)-Notch4 signaling correlates with angiogenesis in primary glioblastoma: an immunohistochemical study.

Delta-like ligand-4 (DLL4)-Notch signaling is known to play a pivotal role in the regulation of tumor angiogenesis. We had previously found that DLL4 was overexpressed, while Notch1 receptor, which binds to DLL4 during angiogenesis, was absent in the majority of human primary glioblastomas. Thus, DLL4-Notch signaling pathway in the regulation of tumor angiogenesis in primary glioblastoma remains unknown. Tumor tissues from 70 patients with primary glioblastoma were analyzed by immunohistochemistry for expression of components of DLL4-Notch signaling, vascular endothelial growth factor (VEGF), and microvessel density (MVD). Immunohistochemistry results showed that the positive staining of DLL4 and Notch4 was primarily distributed in tumor vascular endothelial cells but rarely detected in tumor cells. However, VEGF, hairy/enhancer of split-1 (HES1; a target gene of Notch signaling), and Notch1-3 expression was seen in both tumor vascular endothelial cells and tumor cells. Univariate analysis showed that the expression levels of VEGF and DLL4, HES1, and Notch4 in tumor endothelial cells were significantly associated with MVD in primary glioblastoma (P < 0.001). Binary logistic regression analysis showed that high expression levels of DLL4, HES1, and Notch4 in tumor endothelial cells were associated with a decrease of MVD in primary glioblastoma, while MVD increased with elevated VEGF expression in contrast. In addition, DLL4, Notch4, and HES1 expression were positively correlated in tumor vascular endothelial cells (P < 0.05). We conclude that the vascular DLL4-Notch4 signaling and VEGF signaling complementing each other plays an important role in the progression of tumor angiogenesis in primary glioblastoma. Graphical abstract A, positive staining of DLL4 in human kidney; B, positive staining of VEGF in human breast cancer; C, positive staining of CD34 in human lung cancer; D, positive staining of HES1 in human breast cancer; E-H, positive staining of Notch1-4: E-F in human lung cancer; G-H in human kidney.

The Vascular Notch Ligands Delta-Like Ligand 4 (DLL4) and Jagged1 (JAG1) Have Opposing Correlations with Microvascularization but a Uniform Prognostic Effect in Primary Glioblastoma: A Preliminary Study.

PURPOSE: Delta-like ligand 4 (DLL4) and Jagged1 (JAG1), 2 vascular Notch ligands, are involved in the process of tumor angiogenesis. The present study investigates their relationship with microvascularization and the prognostic effect in primary glioblastoma. METHODS: Tumor tissues from 61 glioblastomas were analyzed using immunohistochemistry for DLL4/JAG1 expression and microvascular formations. The correlations between DLL4/JAG1 and microvascularization were analyzed. The survival probabilities were computed using the Kaplan-Meier method. The Cox proportional hazards regression model was used for multivariate analysis of time to progression (TTP) and overall survival (OS). RESULTS: The results showed increased DLL4 and JAG1 expression in glioblastoma tissues. Five types of basic microvascular formations, including microvascular sprouting, vascular cluster, vascular garland, glomeruloid vascular proliferation, and vasculogenic mimicry, were detected. Glioblastomas with the type I microvascular pattern (MVP) that displayed prominent microvascular sprouting and vascular clusters tended to have higher DLL4 expression, whereas those with the type II MVP that had numerous vascular garlands, glomeruloid vascular proliferations, and vasculogenic mimicries showed upregulated JAG1 expression. Univariate analysis documented that high DLL4 expression, high JAG1 expression, and type II (MVP) were statistically associated with reduced TTP and OS. Multivariate analysis confirmed high DLL4 expression, high JAG1 expression, and type II MVP as significant prognostic factors for both shorter TTP and OS, independent of age, Karnofsky performance scale, and other molecular markers (vascular endothelial growth factor, Ki67, and P53). CONCLUSIONS: DLL4 and JAG1 may have opposing effects on tumor angiogenesis in glioblastoma. The Notch pathway may be a new target for antiangiogenic therapy in glioblastoma.

Peritumoral edema on magnetic resonance imaging predicts a poor clinical outcome in malignant glioma.

Peritumoral edema (PTE), one of the main characteristics of malignant glioma, is a significant contributor to the morbidity and mortality from glioma, however, a recent systematic review suggested that controversy remains with regard to its prognostic value. To further determine whether PTE was a potential prognostic factor on routine pre-operative magnetic resonance imaging (MRI) for malignant glioma, the association between survival and PTE was investigated in the present retrospective review of 109 patients with newly diagnosed supratentorial malignant glioma using MRI data from these routine scans. The Kaplan-Meier method was used to calculate overall survival (OS) in univariate analysis, and COX proportional hazards model was applied to evaluate the effect of pre-operative MRI features on OS in multivariate analysis. The PTE extent, edema shape, degree of necrosis, enhancement extent, pathological grade, patient age, Karnofsky performance status (KPS) and post-operative chemoradiotherapy were associated with OS in the patients with malignant glioma on univariate analysis. Multivariate analysis indicated that the extent of PTE and degree of necrosis shown by pre-operative MRI were independent predictors of OS, in addition to pathological grade, patient age, KPS and post-operative chemoradiotherapy. Moreover, patients with two unfavorable factors (major edema and severe necrosis) exhibited a poorer OS compared with the remainder. In summary, PTE and degree of necrosis, which are easily determined from routine MRI, can be useful for predicting a poor clinical outcome in patients with newly diagnosed malignant glioma.

High Jagged1 expression is associated with poor outcome in primary glioblastoma.

Glioblastoma is a highly aggressive brain tumor. Aberrant Notch pathway has been implicated in the formation and progression of glioblastoma. The present study attempted to investigate the expression of Notch ligand Jagged1 and its association with patient outcome in primary glioblastoma. Tumor tissues from 82 patients with primary glioblastoma were analyzed using immunohistochemistry for Jagged1 expression. Relationships between Jagged1 expression and clinical features (age, gender, KPS, symptom duration, extent of resection and Ki67 index) were evaluated. The prognostic value of Jagged1 was assessed using the Kaplan-Meier survival estimates and the Cox proportional hazard models. Immunohistochemistry results showed markedly increased Jagged1 expression in glioblastoma tissues compared to adjacent non-neoplastic brain tissues. Univariate analysis documented that high Jagged1 expression in tumor cells (TC) and endothelial cells (EC) were both statistically associated with reduced time to progression (TTP) (P < 0.001 for TC, P = 0.001 for EC) and overall survival (OS) (P < 0.001 for TC, P = 0.003 for EC) in primary glioblastoma. The median TTP (P < 0.001) and OS (P = 0.001) were higher in patients with dual-low Jagged1 expression in TC and EC compared to those in patients with non-dual Jagged1 expression and dual high expression. By multivariate survival analysis, we found that high Jagged1 expression in both tumor cells and endothelial cells was independent unfavorable prognostic factors TTP (P < 0.001 for TC, P < 0.001 for TC) and OS (P < 0.001 for TC, P < 0.001 for TC) in primary glioblastoma patients. Jagged1-Notch signaling plays an important role in the progress of glioblastoma. Jagged1 expression may be used as an independent prognosis factor in patients with glioblastoma.

Correlation of high delta-like ligand 4 expression with peritumoral brain edema and its prediction of poor prognosis in patients with primary high-grade gliomas.

OBJECT: Peritumoral brain edema (PTBE) is a common phenomenon associated with high-grade gliomas (HGGs). In this study, the authors investigated the expression of Notch delta-like ligand 4 (DLL4) and its correlation with PTBE and prognosis in patients with an HGG. METHODS: Tumors from 99 patients with HGG were analyzed for DLL4 expression using immunohistochemistry. PTBE on preoperative MR images and the relationship between PTBE and DLL4 expression were evaluated. The effect of DLL4 on patient prognosis was assessed by using Kaplan-Meier survival and Cox proportional hazard models. RESULTS: Immunohistochemistry results revealed that the expression of DLL4 was distributed primarily within the cytoplasm of tumor vascular endothelial cells and seldom detected in tumor cells. DLL4 expression was correlated positively with the degree of edema (r = 0.845 and p < 0.001, Spearman's test). In addition, DLL4 was an independent predictor of prognosis in patients with HGGs (p = 0.001). CONCLUSIONS: DLL4 expression was correlated positively with the degree of PTBE and was an independent unfavorable prognostic indicator in patients with HGG.

High delta-like ligand 4 (DLL4) is correlated with peritumoral brain edema and predicts poor prognosis in primary glioblastoma.

Delta-like ligand 4 (DLL4), 1 of the 5 known Notch ligands, is involved in a variety of tumor initiation and progression, particularly in the process of tumor angiogenesis. However, the clinical and prognostic significance of DLL4 in glioblastoma have not been fully elucidated.Tumor tissues from 69 glioblastoma patients were analyzed using immunohistochemistry for DLL4 expression. Peritumoral brain edema (PTBE) on preoperative magnetic resonance imaging of these patients and the relationship with DLL4 expression were evaluated. The effect on prognosis was assessed by using the Kaplan-Meier survival and the Cox proportional hazard model.The results showed that elevated DLL4 expression was primarily distributed in the cytoplasm of tumor vascular endothelial cells and rarely detected in tumor cells. Univariate analysis indicated significant correlation of high DLL4 expression with shorter time to progression (TTP) (P < 0.001) and overall survival (OS) (P < 0.001) in glioblastoma. Multivariate analysis confirmed high DLL4 expression as an unfavorable prognostic indicator for TTP (P < 0.001) and OS (P < 0.001), independent of age, gender, symptom duration, resection degree, and PTBE. Importantly, the study also found that DLL4 expression was positively related with PTBE (Spearman's test: r = 0.845, P < 0.001). A multiple linear regression model was constructed to confirm that the positive index of DLL4 was associated with an increase in maximum extent of PTBE (P < 0.001).It is thus concluded that DLL4 is correlated with PTBE and may be useful for predicting prognosis in glioblastoma.