FGF2 as a potential prognostic biomarker for proneural glioma patients

A systematic review verified by bioinformatic analysis based on TCGA reveals week prognosis power of CAIX in renal cancer

BACKGROUND

Carbonic anhydrase IX (CAIX) protein has been correlated with progression and survival in patients with some tumors such as head and neck carcinoma. But renal cell carcinoma is an exception. The prognostic value of CAIX in RCC used to be associated with patients' survival according to published works. This study aimed to rectify the former conclusion.

METHODS

This study was registered in PROSPERO (CRD42020160181). A literature search of the PubMed, Embase, Cochrane library and Web of Science databases was performed to retrieve original studies until April of 2022. Twenty-seven studies, including a total of 5462 patients with renal cell carcinoma, were reviewed. Standard meta-analysis methods were used to evaluate the prognostic impact of CAIX expression on patient prognosis. The hazard ratio and its 95% confidence interval were recorded for the relationship between CAIX expression and survival, and the data were analyzed using Stata 11.0. Then we verify the meta-analysis resort to bioinformatics (TCGA).

RESULTS

Our initial search resulted in 908 articles in total. From PubMed, Embase, Web of Science electronic and Cochrane library databases, 493, 318 and 97 potentially relevant articles were discovered, respectively. We took the analysis between CA9 and disease-specific survival (HR = 1.18, 95% CI: 0.82-1.70, I2 = 79.3%, P<0.05), a subgroup then was performed to enhance the result (HR = 1.63, 95%CI: 1.30-2.03, I2 = 26.3%, P = 0.228); overall survival was also parallel with the former (HR = 1.13, 95%CI: 0.82-1.56, I2 = 79.8%, P<0.05), then a subgroup also be performed (HR = 0.90, 95%CI:0.75-1.07, I2 = 23.1%, P = 0.246) to verify the result; the analysis between CAIX and progression-free survival got the similar result (HR = 1.73, 95%CI:0.97-3.09, I2 = 82.4%, P<0.05), we also verify the result by subgroup analysis (HR = 1.04, 95%CI:0.79-1.36, I2 = 0.0%, P = 0.465); at last the relationship between CAIX and recurrence-free survival got the same result, too (HR = 0.99, 95%CI: 0.95-1.02, I2 = 57.8%, P = 0.050), the subgroup's result was also parallel with the former (HR = 1.01, 95%CI: 0.91-1.03, I2 = 0.00%, P = 0.704). To validate our meta-analysis, we took a bioinformatic analysis based on TCGA database, survival curve between low and high CAIX expression in four endpoints (DSS, OS, PFI, DFI) have corresponding P value (DSS:P = 0.23, OS:P = 0.77, PFI:P = 0.25, DFI:P = 0.78).

CONCLUSIONS

CAIX expression in patients with RCC is an exception to predict tumor survival. Both low CAIX expression and high expression are not associated with survivals in RCC patients.

Understanding metabolic alterations and heterogeneity in cancer progression through validated immunodetection of key molecular components: a case of carbonic anhydrase IX

Cancer metabolic heterogeneity develops in response to both intrinsic factors (mutations leading to activation of oncogenic pathways) and extrinsic factors (physiological and molecular signals from the extracellular milieu). Here we review causes and consequences of metabolic alterations in cancer cells with focus on hypoxia and acidosis, and with particular attention to carbonic anhydrase IX (CA IX). CA IX is a cancer-associated enzyme induced and activated by hypoxia in a broad range of tumor types, where it participates in pH regulation as well as in molecular mechanisms supporting cancer cells’ invasion and metastasis. CA IX catalyzes reversible conversion of carbon dioxide to bicarbonate ion plus proton and cooperates with a spectrum of molecules transporting ions or metabolites across the plasma membrane. Thereby CA IX contributes to extracellular acidosis as well as to buffering intracellular pH, which is essential for cell survival, metabolic performance, and proliferation of cancer cells. Since CA IX expression pattern reflects gradients of oxygen, pH, and other intratumoral factors, we use it as a paradigm to discuss an impact of antibody quality and research material on investigating metabolic reprogramming of tumor tissue. Based on the validation, we propose the most reliable CA IX-specific antibodies and suggest conditions for faithful immunohistochemical analysis of molecules contributing to heterogeneity in cancer progression.

Association of glioma CD44 expression with glial dynamics in the tumour microenvironment and patient prognosis

Because of the heterogeneity of lower-grade gliomas (LGGs), patients show various survival outcomes that are not reliably predicted by histological classification. The tumour microenvironment (TME) contributes to the initiation and progression of brain LGGs. Identifying potential prognostic markers based on the immune and stromal components in the TME will provide new insights into the dynamic modulation of these two components of the TME in LGGs. We applied ESTIMATE to calculate the ratio of immune and stromal components from The Cancer Genome Atlas database. After combined differential gene expression analysis, protein–protein interaction network construction and survival analysis, CD44 was screened as an independent prognostic factor and subsequently validated utilizing data from the Chinese Glioma Genome Atlas database. To decipher the association of glioma cell CD44 expression with stromal cells in the TME and tumour progression, RT–qPCR, cell viability and wound healing assays were employed to determine whether astrocytes enhance glioma cell viability and migration by upregulating CD44 expression. Surprisingly, M1 macrophages were identified as positively correlated with CD44 expression by CIBERSORT analysis. CD44⁺ glioma cells were further suggested to interact with microglia-derived macrophages (M1 phenotype) via osteopontin signalling on the basis of single-cell sequencing data. Overall, we found that astrocytes could elevate the CD44 expression level of glioma cells, enhancing the recruitment of M1 macrophages that may promote glioma stemness via osteopontin-CD44 signalling. Thus, glioma CD44 expression might coordinate with glial activities in the TME and serve as a potential therapeutic target and prognostic marker for LGGs.

Endothelial cell-specific reduction of heparan sulfate suppresses glioma growth in mice

PURPOSE

Heparan sulfate (HS) is one of the factors that has been suggested to be associated with angiogenesis and invasion of glioblastoma (GBM), an aggressive and fast-growing brain tumor. However, it remains unclear how HS of endothelial cells is involved in angiogenesis in glioblastoma and its prognosis. Thus, we investigated the effect of endothelial cell HS on GBM development.

METHODS

We generated endothelial cell-specific knockout of Ext1, a gene encoding a glycosyltransferase and essential for HS synthesis, and murine GL261 glioblastoma cells were orthotopically transplanted. Two weeks after transplantation, we examined the tumor progression and underlying mechanisms.

RESULTS

The endothelial cell-specific Ext1 knockout (Ext1 CKO ) mice exhibited reduced HS expression specifically in the vascular endothelium of the brain capillaries compared with the control wild-type (WT) mice. GBM growth was significantly suppressed in Ext1 CKO mice compared with that in WT mice. After GBM transplantation, the survival rate was significantly higher in Ext1 CKO mice than in WT mice. We investigated how the effect of fibroblast growth factor 2 (FGF2), which is known as an angiogenesis-promoting factor, differs between Ext1 CKO and WT mice by using an in vivo Matrigel assay and demonstrated that endothelial cell-specific HS reduction attenuated the effect of FGF2 on angiogenesis.

CONCLUSIONS

HS reduction in the vascular endothelium of the brain suppressed GBM growth and neovascularization in mice.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12672-021-00444-3.

Lnc-H19 enhances anaerobic glycolysis of keloid fibroblasts by targeting the miR-214-5p/FGF2 axis

Long non-coding RNA (lncRNA) H19 has been demonstrated as vital regulator in tumors. However, whether lnc-H19 mediated the development of keloid fibroblasts (KD) was unknown, this study was aimed to clarify the role and molecular mechanisms of lnc-H19 in KD. We have investigated the expression levels of lnc-H19, miR-214-5p and fibroblast growth factor 2 (FGF2) in KD skin samples and normal skin tissues as well as matched cells by real-time quantitative polymerase chain reaction (RT-qPCR) assay. The glycolysis ability of keloid fibroblasts was assessed by measuring glucose consumption, lactate production, and ATP level. The western blot assay was used to assay the expression levels of FGF2 and hexokinase 2 (HK2). Migration and invasion were analyzed by transwell in keloid fibroblasts. The bioinformatics database and dual-luciferase reporter assay were used to search and identify the target of miR-214-5p and lnc-H19. Lnc-H19 was overexpressed in KD tissues and keloid fibroblasts than normal skin tissues and normal fibroblasts, respectively. Small interfering RNA of lnc-H19 treatment markedly inhibited glycolysis, migration and invasion of keloid fibroblasts exposed to hypoxia, which was reserved by silencing of miR-214-5p or upregulation of FGF2. Mechanistically, lnc-H19 regulated KD development by regulation of miR-214-5p/FGF2 axis. In summary, lnc-H19 may exert regulatory functions in KD by targeting miR-214-5p/FGF2 axis, further regulated glycolysis, migration and invasion in keloid fibroblasts exposed to hypoxia, which might be a potential marker of KD diagnosis or progression.

Expression of CD44 and the survival in glioma: a meta-analysis

Background: Higher tumor expression of CD44, a marker of cancer stem cells (CSCs), is associated with poor overall survival (OS) in various cancers. However, the association between CD44 and poor OS remains inconsistent in glioma. We aimed to evaluate the potential predictive role of CD44 for prognosis of glioma patients in a meta-analysis.

Methods: Observational studies comparing OS of glioma patients according to the level of CD44 were identified through searching PubMed, Embase, and Cochrane’s Library databases. Meta-analyses were performed with a random- or fixed-effect model according to the heterogeneity. Subgroup analyses were performed to evaluate the influences of study characteristics.

Results: Eleven retrospective cohort studies were included. Results showed that increased CD44 expression in tumor predicted poor OS in glioma patients (hazard ratio [HR]: 1.42, 95% confidence interval [CI]: 1.02–1.97, P=0.04). Subgroup analyses showed that higher tumor CD44 expression significantly predicted poor OS in patients with World Health Organization (WHO) stages II–III glioma (HR: 2.99, 95% CI: 1.53–5.89, P=0.002), but not in patients with glioblastoma (HR: 1.26, 95% CI: 0.76–2.08, P=0.47; P for subgroup difference = 0.03). Results were not statistically different between subgroups according to patient ethnicity, sample size, CD44 detection method, CD44 cutoff, HR estimation, univariate or multivariate analysis, or median follow-up durations (P-values for subgroup difference all >0.10).

Conclusion: Higher tumor expression of CD44 may predict poor survival in patients with glioma, particularly in those with WHO stage II–III glioma.

A novel gene signature based on five immune checkpoint genes predicts the survival of glioma

BACKGROUND

Glioma is the most common and fatal type of nerve neoplasm in the central nervous system. Several biomarkers have been considered for prognosis prediction, which is not accurate enough. We aimed to carry out a gene signature related to the expression of immune checkpoints which was enough for its performance in prediction.

METHODS

Gene expression of immune checkpoints in TGGA database was filtrated. The 5 selected genes underwent verification by COX and Lasso-COX regression. Next, the selected genes were included to build a novel signature for further analysis.

RESULTS

Patients were sub-grouped into high and low risk according to the novel signature. Immune response, clinicopathologic characters, and survival showed significant differences between those 2 groups. Terms including "naive," "effector," and "IL-4" were screened out by GSEA. The results showed strong relevance between the signature and immune response.

CONCLUSIONS

We constructed a gene signature with 5 immune checkpoints. The signature predicted survival effectively. The novel signature performed more functional than previous biomarkers.

FGF2: a novel druggable target for glioblastoma?

Introduction: Fibroblast growth factors (FGFs) are key mitogens in tissue homeostasis and cancer. FGF2 regulates self-renewal of multiple stem-cell types, is widely used in stem cell culture paradigms and has been adopted for cultivating the growth of cancer stem cells ex vivo. Research has shed light on the functions of FGF2 in brain tumors, particularly malignant glioma, and this has demonstrated that FGF2 increases self-renewal of glioblastoma stem cells.Areas covered: This review examines the potential targeting of FGF2 signaling as a possible treatment avenue for glioblastoma. The expression of FGF ligands and the FGFR family of receptor tyrosine kinases in the normal brain and in glioblastoma is described. Moreover, the paper sheds light on FGF/FGFR signaling, including the function of heparin/heparan sulfate proteoglycans in facilitating FGF signaling. We speculate on potential avenues for the therapeutic targeting of the FGF2-FGF receptor signaling axis in glioblastoma and the associated challenges envisioned with these approaches.Expert opinion: Precision targeting of FGF/FGFR signaling could improve prospective glioblastoma therapeutics and moderate adverse effects. Shrewd development of experimental models and FGF2 inhibitors could provide a 'pharmacological toolbox' for targeting diverse ligand/receptor combinations.

Tumor Development and Angiogenesis in Adult Brain Tumor: Glioblastoma

Angiogenesis is the growth of new capillaries from the preexisting blood vessels. Glioblastoma (GBM) tumors are highly vascularized tumors, and glioma growth depends on the formation of new blood vessels. Angiogenesis is a complex process involving proliferation, migration, and differentiation of vascular endothelial cells (ECs) under the stimulation of specific signals. It is controlled by the balance between its promoting and inhibiting factors. Various angiogenic factors and genes have been identified that stimulate glioma angiogenesis. Therefore, attention has been directed to anti-angiogenesis therapy in which glioma proliferation is inhibited by inhibiting the formation of new tumor vessels using angiogenesis inhibitory factors and drugs. Here, in this review, we highlight and summarize the various molecular mediators that regulate GBM angiogenesis with focus on recent clinical research on the potential of exploiting angiogenic pathways as a strategy in the treatment of GBM patients.

Bevacizumab has bidirectional regulatory effects on the secretion of basic fibroblast growth factor in glioma cells

Previous studies suggest that upregulated basic fibroblast growth factor (bFGF) plays a key role in the resistance to anti-vascular endothelial growth factor (VEGF) therapy in glioma. This study reported that anti-VEGF treatment regulated bFGF secretion in a double-edged manner. That is, moderate VEGF neutralization reduced bFGF production, whereas VEGF overblocking enhanced bFGF secretion in glioma cells. Our data provide a new perspective on the treatment of glioma with anti-VEGF, and the underlying mechanism is worthy of further study.

MicroRNA-936 targets FGF2 to inhibit epithelial ovarian cancer aggressiveness by deactivating the PI3K/Akt pathway

Purpose

MicroRNA-936 (miR-936) was previously reported to be dysregulated and involved in the development of non-small cell lung cancer and glioma. However, the functional roles of miR-936 in epithelial ovarian cancer (EOC) remain unclear. In this study, we aimed to evaluate miR-936 expression in EOC and investigate its regulatory role in EOC cell behavior.

Methods

The expression of miR-936 in EOC was measured by RT-qPCR. Cell proliferation, apoptosis, migration, and invasion in vitro, as well as tumor growth in vivo, were determined by CCK-8, flow cytometry, migration and invasion assays, and xenograft models in nude mice, respectively. Bioinformatics analysis, luciferase reporter assays, RT-qPCR, and Western blot analysis were performed to investigate the relationship between miR-936 and fibroblast growth factor 2 (FGF2).

Results

miR-936 expression was significantly downregulated in EOC tissues and cell lines. Low miR-936 expression was found to be correlated with the tumor size, FIGO stage, and lymphatic metastasis in EOC patients. Functional experiments indicated that ectopic miR-936 expression suppressed EOC cell proliferation, migration, and invasion; promoted cell apoptosis; and decreased tumor growth in vivo. In addition, the FGF2 gene was verified to be a direct target of miR-936 in EOC cells. FGF2 expression levels were upregulated in EOC tissues and were inversely correlated with miR-936 expression. Furthermore, effects of FGF2 silencing were similar to those of miR-936 overexpression in EOC cells. Recovered FGF2 expression rescued the miR-936-induced inhibitory effects in EOC cells. Notably, miR-936 was able to deactivate the PI3K/Akt signaling pathway in EOC cells by regulating FGF2 both in vitro and in vivo.

Conclusion

Altogether, our findings provided initial evidence that miR-936 inhibits the aggressiveness of EOC cells in vitro and in vivo, at least partially, by targeting FGF2-mediated suppression of the PI3K/Akt pathway. Therefore, the miR-936/FGF2/PI3K/Akt pathway is a promising therapeutic target for the treatment of EOC patients.

MicroRNA-497-5p inhibits proliferation and invasion of non-small cell lung cancer by regulating FGF2

Increasing number of microRNAs (miRNAs) have been reported to play an important role in the development and progression of non-small cell lung cancer (NSCLC). In particular, microRNA-497-5p (miR-497-5p) has been proposed as a tumor suppressor miRNA in human cancers. However, the role of miR-497-5p and its potential molecular mechanism associated with NSCLC are less studied. Therefore, the role of miR-497-5p in the pathogenesis of NSCLC was investigated. In the present study, the expression of miR-497-5p was significantly downregulated in NSCLC. Moreover, overexpression of miR-497-5p inhibited the proliferation and invasion of NSCLC cells by suppressing FGF2. In addition, FGF2 was a downstream target of miR-497-5p in NSCLC. FGF2 was upregulated in NSCLC promoting cell proliferation and invasion. Overexpression of FGF2 impaired the inhibitory effect of miR-497-5p in NSCLC. Taken together, these results demonstrate that miR-497-5p is a tumor suppressor miRNA and demonstrate its potential for future use in the treatment of human NSCLC.

PROX1 is a novel pathway-specific prognostic biomarker for high-grade astrocytomas; results from independent glioblastoma cohorts stratified by age and IDH mutation status

PROX1 is a transcription factor with an essential role in embryonic development and determination of cell fate. In addition, PROX1 has been ascribed suppressive as well as oncogenic roles in several human cancers, including brain tumors. In this study we explored the correlation between PROX1 expression and patient survival in high-grade astrocytomas. For this purpose, we analyzed protein expression in tissue microarrays of tumor samples stratified by patient age and IDH mutation status. We initially screened 86 unselected high-grade astrocytomas, followed by 174 IDH1-R132H1 immunonegative glioblastomas derived from patients aged 60 years and older enrolled in the Nordic phase III trial of elderly patients with newly diagnosed glioblastoma. Representing the younger population of glioblastomas, we studied 80 IDH-wildtype glioblastomas from patients aged 18-60 years. There was no correlation between PROX1 protein and survival for patients with primary glioblastomas included in these cohorts. In contrast, high expression of PROX1 protein predicted shorter survival in the group of patients with IDH-mutant anaplastic astrocytomas and secondary glioblastomas. The prognostic impact of PROX1 in IDH-mutant 1p19q non-codeleted high-grade astrocytomas, as well as the negative findings in primary glioblastomas, was corroborated by gene expression data extracted from the Cancer Genome Atlas. We conclude that PROX1 is a new prognostic biomarker for 1p19q non-codeleted high-grade astrocytomas that have progressed from pre-existing low-grade tumors and harbor IDH mutations.

A novel gene signature based on five glioblastoma stem-like cell relevant genes predicts the survival of primary glioblastoma

PURPOSE

Primary glioblastoma (pGBM) is the most common and lethal type of neoplasms in the central nervous system, while the existing biomarkers, lacking consideration on the stemness changes of GBM cells, are not specific enough to predict the complex prognosis respectively. We aimed to build a high-efficiency prediction gene signature related to GBM cell stemness and investigate its prognostic value in primary glioblastoma.

METHODS

Differentially expressed genes were screened in GSE23806 database. The selected genes were then verified by univariate Cox regression in 591 patients from four enormous independent databases, including the Chinese Glioma Genome Atlas (CGGA), TCGA, REMBRANDT and GSE16011. Finally, the intersected genes were included to build the gene signature. GO analysis and GSEA were carried out to explore the bioinformatic implication.

RESULTS

The novel five-gene signature was used to identify high- and low-risk groups in the four databases, and the high-risk group showed notably poorer prognosis (P < 0.05). Gene ontology (GO) terms including "immune response", "apoptotic process", and "angiogenesis" were picked out by GO analysis and GSEA, which revealed that the gene signature was highly possibly related to the stemness of GSCs and predicting the prognosis of GBM effectively.

CONCLUSION

We built a gene signature with five glioblastoma stem-like cell (GSC) relevant genes, and predicted the survival in four independent databases effectively, which is possibly related to the stemness of GSCs in pGBM. Several GO terms were investigated to be correlated to the signature. The signature can predict the prognosis of glioblastoma efficiently.

Dual Functional MicroRNA-186-5p Targets both FGF2 and RelA to Suppress Tumorigenesis of Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is one of the most malignant cancers. MicroRNAs (miRs) were reported to play important roles in GBM recently. However, the role of a novel miR-186-5p in GBM tumorigenesis is still elusive. Using bioinformatics, miR-186-5p was identified as potential regulators of both fibroblast growth factor (FGF)-2 and NF-κB subunit RelA. Luciferase reporter assay was used to confirm the direct recognition FGF2 and RelA mRNAs by miR-186-5p. Invasion and migration assays were employed to study the effect of miR-186-5p on GBM cell growth in vitro. Xenograft tumor animal model was established to elucidate the in vivo function of miR-186-5p. MiR-186-5p directly targeted mRNAs of both FGF2 and RelA, and repressed their expressions. Invasive and migratory abilities of GBM cells and growth of xenograft tumors were significantly inhibited by miR-186-5p, which can be restored by re-introduction of FGF2 and RelA expressions. MiR-186-5p is a novel tumor suppressor miR that functions to inhibit tumorigenesis of GBM both in vitro and in vivo, by targeting both FGF2 and RelA. MiR-186-5p/FGF2/RelA pathway may be potentially used as molecular targets of in the clinical treatment of GBM.

Tumor suppressors microRNA-302d and microRNA-16 inhibit human glioblastoma multiforme by targeting NF-κB and FGF2

MicroRNA-302d and microRNA-16 inhibit glioblastoma multiforme by targeting NF-κB p65 and FGF2.

NCAM- and FGF-2-mediated FGFR1 signaling in the tumor microenvironment of esophageal cancer regulates the survival and migration of tumor-associated macrophages and cancer cells

Tumor-associated macrophages (TAMs) have important roles in the angiogenesis and tumor immunosuppression of various cancers, including esophageal squamous cell carcinomas (ESCCs). To elucidate the roles of TAMs in ESCCs, we compared the gene expression profiles between human peripheral blood monocyte-derived macrophage-like cells (Macrophage_Ls) and Macrophage_Ls stimulated with conditioned medium of the TE series human ESCC cell line (TECM) (TAM_Ls) using cDNA microarray analysis. Among the highly expressed genes in TAM_Ls, we focused on neural cell adhesion molecule (NCAM). NCAM knockdown in TAM_Ls revealed a significant decrease of migration and survival via a suppression of PI3K-Akt and fibroblast growth factor receptor 1 (FGFR1) signaling. Stimulation by TECM up-regulated the level of FGFR1 in Macrophage_Ls. Recombinant human fibroblast growth factor-2 (rhFGF-2) promoted the migration and survival of TAM_Ls and TE-cells through FGFR1 signaling. Our immunohistochemical analysis of 70 surgically resected ESCC samples revealed that the up-regulated FGF-2 in stromal cells, including macrophages, was associated with more aggressive phenotypes and a high number of infiltrating M2 macrophages. These findings may indicate a novel role of NCAM- and FGF-2-mediated FGFR1 signaling in the tumor microenvironment of ESCCs.

Prognostic Significance of Carbonic Anhydrase IX Expression in Cancer Patients: A Meta-Analysis

Hypoxia is a characteristic of many solid tumors and an adverse prognostic factor for treatment outcome. Hypoxia increases the expression of carbonic anhydrase IX (CAIX), an enzyme that is predominantly found on tumor cells and is involved in maintaining the cellular pH balance. Many clinical studies investigated the prognostic value of CAIX expression, but most have been inconclusive, partly due to small numbers of patients included. The present meta-analysis was therefore performed utilizing the results of all clinical studies to determine the prognostic value of CAIX expression in solid tumors. Renal cell carcinoma was excluded from this meta-analysis due to an alternative mechanism of upregulation. 958 papers were identified from a literature search performed in PubMed and Embase. These papers were independently evaluated by two reviewers and 147 studies were included in the analysis. The meta-analysis revealed strong significant associations between CAIX expression and all endpoints: overall survival [hazard ratio (HR) = 1.76, 95% confidence interval (95%CI) 1.58–1.98], disease-free survival (HR = 1.87, 95%CI 1.62–2.16), locoregional control (HR = 1.54, 95%CI 1.22–1.93), disease-specific survival (HR = 1.78, 95%CI 1.41–2.25), metastasis-free survival (HR = 1.82, 95%CI 1.33–2.50), and progression-free survival (HR = 1.58, 95%CI 1.27–1.96). Subgroup analyses revealed similar associations in the majority of tumor sites and types. In conclusion, these results show that patients having tumors with high CAIX expression have higher risk of locoregional failure, disease progression, and higher risk to develop metastases, independent of tumor type or site. The results of this meta-analysis further support the development of a clinical test to determine patient prognosis based on CAIX expression and may have important implications for the development of new treatment strategies.

New perspectives in glioblastoma antiangiogenic therapy

Glioblastoma (GB) is highly vascularised tumour, known to exhibit enhanced infiltrative potential. One of the characteristics of glioblastoma is microvascular proliferation surrounding necrotic areas, as a response to a hypoxic environment, which in turn increases the expression of angiogenic factors and their signalling pathways (RAS/RAF/ERK/MAPK pathway, PI3K/Akt signalling pathway and WTN signalling cascade). Currently, a small number of anti-angiogenic drugs, extending glioblastoma patients survival, are available for clinical use. Most medications are ineffective in clinical therapy of glioblastoma due to acquired malignant cells or intrinsic resistance, angiogenic receptors cross-activation and redundant intracellular signalling, or the inability of the drug to cross the blood-brain barrier and to reach its target in vivo. Researchers have also observed that GB tumours are different in many aspects, even when they derive from the same tissue, which is the reason for personalised therapy. An understanding of the molecular mechanisms regulating glioblastoma angiogenesis and invasion may be important in the future development of curative therapeutic approaches for the treatment of this devastating disease.