Epidemiology

The role of informal caregivers for patients with glioma: a systematic review and meta-synthesis of qualitative studies

Background

This study aimed to systematically review, appraise, and synthesize the current evidence on the experiences and needs encountered by informal caregiver of patients with glioma throughout the disease trajectory and to provide a set of practical implications for health professionals.

Methods

Seven English databases and four Chinese databases were searched in this systematic review and meta-analysis. Additional manual searches were completed to identify primary studies, with the language limited by English and Chinese. The Joanna Briggs Institute (JBI) Critical Appraisal Checklist for Qualitative Research was used to appraise the methodological quality of each study.

Results

The systematic review included 16 papers that yielded 71 findings and 6 categories. Finally, 2 synthesized findings were extracted: (I) role transition of caregivers for glioma patients throughout the disease trajectory; (II) support and information need by caregivers of glioma patients. Accordingly, there is a need to recognize the importance of permanent and tailored support for caregivers by providing accurate, practical, and evidence-based information.

Discussion

This is the first attempt to systematically evaluate the breadth and quality of the literature concerning the experiences of caregivers with glioma patients. The results generated from the review may shed some light on problems encountered by glioma patients and their families. A limitation of this review is that in most selected studies, the reflexivity of interviewees is not addressed, which may influence the interpretation of the findings. Moreover, the selected studies were reported in English or Chinese, therefore, caution is needed in interpreting the results.

The Prognostic Role and Nomogram Establishment of a Novel Prognostic Score Combining with Fibrinogen and Albumin Levels in Patients with WHO Grade II/III Gliomas

Purpose

World Health Organization (WHO) Grades II and III gliomas [also known as low grade gliomas (LGGs)] displayed different malignant behaviors and survival outcomes compared to Grade IV gliomas. This study aimed to identify the prognostic predictive value of a novel cumulative prognostic score [combined with fibrinogen and albumin levels (FA score)], establish and validate a point-based nomogram in LGG patients.

Patients and Methods

A total of 91 patients who underwent total glioma resection at Shengjing Hospital of China Medical University between 2011 and 2013 were enrolled to establish a prognostic nomogram. All patients were histologically diagnosed as grades II/III, and never received radiotherapy or chemotherapy before surgery. Data collection included patient characteristics, clinicopathological factors, and preoperative hematology results. The performance of the nomogram was subsequently validated by the concordance index (c-index), calibration curve, and receiver operating characteristic (ROC) curve.

Results

The FA score was negatively associated with the overall survival (OS) of LGG patients (p < 0.001). The results of multivariate analysis showed that FA score [p = 0.006, HR = 1.92, 95% confidence interval (CI): 1.21–3.05], age (p = 0.002, HR = 3.014, 95% CI:1.52–5.97), and white blood count (p < 0.001, HR = 4.24, 95% CI: 2.08–8.67) were independent prognostic factors for overall survival (OS). The study established a nomogram to predict OS with a c-index of 0.783 (95% CI, 0.72–0.84).

Conclusion

FA score might be a potential prognostic biomarker for LGG patients, and a reliable point-based nomogram will help clinicians to decide on the best treatment plans.

Comparative evaluation of intracranial oligodendroglioma and astrocytoma of similar grades using conventional and T1-weighted DCE-MRI

PURPOSE

This retrospective study was performed on a 3T MRI to determine the unique conventional MR imaging and T1-weighted DCE-MRI features of oligodendroglioma and astrocytoma and investigate the utility of machine learning algorithms in their differentiation.

METHODS

Histologically confirmed, 81 treatment-naïve patients were classified into two groups as per WHO 2016 classification: oligodendroglioma (n = 16; grade II, n = 25; grade III) and astrocytoma (n = 10; grade II, n = 30; grade III). The differences in tumor morphology characteristics were evaluated using Z-test. T1-weighted DCE-MRI data were analyzed using an in-house built MATLAB program. The mean 90th percentile of relative cerebral blood flow, relative cerebral blood volume corrected, volume transfer rate from plasma to extracellular extravascular space, and extravascular extracellular space volume values were evaluated using independent Student's t test. Support vector machine (SVM) classifier was constructed to differentiate two groups across grade II, grade III, and grade II+III based on statistically significant features.

RESULTS

Z-test signified only calcification among conventional MR features to categorize oligodendroglioma and astrocytoma across grade III and grade II+III tumors. No statistical significance was found in the perfusion parameters between two groups and its subtypes. SVM trained on calcification also provided moderate accuracy to differentiate oligodendroglioma from astrocytoma.

CONCLUSION

We conclude that conventional MR features except calcification and the quantitative T1-weighted DCE-MRI parameters fail to discriminate between oligodendroglioma and astrocytoma. The SVM could not further aid in their differentiation. The study also suggests that the presence of more than 50% T2-FLAIR mismatch may be considered as a more conclusive sign for differentiation of IDH mutant astrocytoma.

HOX gene cluster (de)regulation in brain: from neurodevelopment to malignant glial tumours

HOX genes encode a family of evolutionarily conserved homeodomain transcription factors that are crucial both during development and adult life. In humans, 39 HOX genes are arranged in four clusters (HOXA, B, C, and D) in chromosomes 7, 17, 12, and 2, respectively. During embryonic development, particular epigenetic states accompany their expression along the anterior-posterior body axis. This tightly regulated temporal-spatial expression pattern reflects their relative chromosomal localization, and is critical for normal embryonic brain development when HOX genes are mainly expressed in the hindbrain and mostly absent in the forebrain region. Epigenetic marks, mostly polycomb-associated, are dynamically regulated at HOX loci and regulatory regions to ensure the finely tuned HOX activation and repression, highlighting a crucial epigenetic plasticity necessary for homeostatic development. HOX genes are essentially absent in healthy adult brain, whereas they are detected in malignant brain tumours, namely gliomas, where HOX genes display critical roles by regulating several hallmarks of cancer. Here, we review the major mechanisms involved in HOX genes (de)regulation in the brain, from embryonic to adult stages, in physiological and oncologic conditions. We focus particularly on the emerging causes of HOX gene deregulation in glioma, as well as on their functional and clinical implications.

Thioredoxin, Glutathione and Related Molecules in Tumors of the Nervous System

BACKGROUND

Central Nervous System (CNS) tumors have a poor survival prognosis due to their invasive and heterogeneous nature, in addition to the resistance to multiple treatments.

OBJECTIVE

In this paper, the main aspects of brain tumor biology and pathogenesis are reviewed both for primary tumors of the brain, (i.e., gliomas) and for metastasis from other malignant tumors, namely lung cancer, breast cancer and malignant melanoma which account for a high percentage of overall malignant brain tumors. We review the role of antioxidant systems, namely the thioredoxin and glutathione systems, in the genesis and/or progression of brain tumors.

METHODS

Although overexpression of Thioredoxin Reductase (TrxR) and Thioredoxin (Trx) is often linked to increased malignancy rate of brain tumors, and higher expression of Glutathione (GSH) and Glutathione S-Transferases (GST) are associated to resistance to therapy, several knowledge gaps still exist regarding for example, the role of Peroxiredoxins (Prx), and Glutaredoxins (Grx).

CONCLUSION

Due to their central role in redox homeostasis and ROS scavenging, redox systems are potential targets for new antitumorals and examples of innovative therapeutics aiming at improving success rates in brain tumor treatment are discussed.

ABC Transporters at the Blood-Brain Interfaces, Their Study Models, and Drug Delivery Implications in Gliomas

Drug delivery into the brain is regulated by the blood-brain interfaces. The blood-brain barrier (BBB), the blood-cerebrospinal fluid barrier (BCSFB), and the blood-arachnoid barrier (BAB) regulate the exchange of substances between the blood and brain parenchyma. These selective barriers present a high impermeability to most substances, with the selective transport of nutrients and transporters preventing the entry and accumulation of possibly toxic molecules, comprising many therapeutic drugs. Transporters of the ATP-binding cassette (ABC) superfamily have an important role in drug delivery, because they extrude a broad molecular diversity of xenobiotics, including several anticancer drugs, preventing their entry into the brain. Gliomas are the most common primary tumors diagnosed in adults, which are often characterized by a poor prognosis, notably in the case of high-grade gliomas. Therapeutic treatments frequently fail due to the difficulty of delivering drugs through the brain barriers, adding to diverse mechanisms developed by the cancer, including the overexpression or expression de novo of ABC transporters in tumoral cells and/or in the endothelial cells forming the blood-brain tumor barrier (BBTB). Many models have been developed to study the phenotype, molecular characteristics, and function of the blood-brain interfaces as well as to evaluate drug permeability into the brain. These include in vitro, in vivo, and in silico models, which together can help us to better understand their implication in drug resistance and to develop new therapeutics or delivery strategies to improve the treatment of pathologies of the central nervous system (CNS). In this review, we present the principal characteristics of the blood-brain interfaces; then, we focus on the ABC transporters present on them and their implication in drug delivery; next, we present some of the most important models used for the study of drug transport; finally, we summarize the implication of ABC transporters in glioma and the BBTB in drug resistance and the strategies to improve the delivery of CNS anticancer drugs.

Genetic Variants Related to Cell Cycle and Stability of Telomere in Patients with Glioma

Background:

Glioma, most common primary malignant brain tumor in adults, is highly aggressive and associated with a poor prognosis. Evaluate the association of polymorphisms related of to the cell cycle, integrity and DNA repair with gliomas, as well as lifestyle habits, comorbidities, survival and response to treatment.

Methods:

Were studied 303 individuals distributed into: Study Group - 100 patients with gliomas, regardless of the degree of malignancy, and Control Group - 203 individuals without clinical signs of the disease. These polymorphisms were genotyped by TaqMan^® SNP Genotyping Assay. Significance level was set at 5%.

Results:

Smoking, alcohol consumption, systemic arterial hypertension (SAH) and diabetes mellitus (DM) prevailed in patients, compared to controls (P=0.0088, P=0.0001, P=0.0001, P=0.0011, respectively). In the logistic regression analysis, alcohol consumption and SAH were identified as independent risk factors for gliomas (P=0.0001, P=0.0027, respectively). Patients with low-grade gliomas showed survival in one year (92.0±6.8%), compared to patients with high-grade gliomas (24.0±5.3; P=0.011).

Conclusion:

Polymorphisms involved in cell cycle, telomere protection and stability and DNA repair are not associated with gliomas. On the other hand, alcohol consumption and SAH stand out as independent risk factors for the disease. Low-grade gliomas, response to treatment and the combination of chemotherapy with Temozolomide and radiation therapy show increased survival of patients.

Genetic variants related to angiogenesis and apoptosis in patients with glioma

BACKGROUND

Glioma, the most common primary malignant brain tumor in adults, is highly aggressive and associated with a poor prognosis. The objectives of this study were to evaluate the association of genetic polymorphisms related to angiogenesis and apoptosis with gliomas, as well as comorbidities, lifestyle, clinical profile, survival and response to treatment (temozolomide [TMZ] and radiotherapy [RT]) in patients with the disease.

METHODS

In a total of 303 individuals, genotypes were performed by real-time PCR, and clinical data, lifestyle and comorbidities were obtained from medical records and questionnaires. The significance level was set at 5%.

RESULTS

Smoking, alcohol consumption, systemic arterial hypertension, diabetes mellitus and body mass index prevailed among patients, compared to controls (p < 0.05). The heterozygous genotype rs1468727 (T/C) and the homozygous genotype rs2010963 (G/G) (p > 0.05) were observed in both groups. Lifestyle and comorbidities showed independent risk factors for the disease (p < 0.0001, p = 0.0069, p = 0.0394, respectively). Patients with low-grade gliomas had a survival rate of 80.0 ± 1.7% in three years. For the combination of TMZ+RT, survival was 78.7 ± 7.6% in 20 months, compared to TMZ only (21.9 ± 5.1%, p = 0.8711).

CONCLUSIONS

Genetic variants were not associated with gliomas. Specific lifestyle habits and comorbidities stood out as independent risk factors for the disease. Low-grade gliomas showed an increase in patient survival with TMZ+RT treatment.

Tumor suppressor candidate 3: A novel grading tool and predictor of clinical malignancy in human gliomas

For several years, the cause of autosomal recessive mental retardation has been attributed to the deletion or mutation of a gene named tumor suppressor candidate 3 (TUSC3). Previous research has identified that TUSC3 is a potential tumor suppressor gene in oral epidermoid carcinoma, lung cancer and esophageal cancer. However, to the best of our knowledge, no previously published data has existed on the expression of TUSC3 in gliomas. The present study focused on the expression of TUSC3 in brain gliomas. Additionally, the present study sought to identify he association between TUSC3 expression and the typical clinical and pathological disease manifestations of gliomas. TUSC3 levels were evaluated using a western blot assay and immunohistochemistry on tissue microarray slides. Results indicated a significant decrease in TUSC3 expression in glioma tissues compared with the normal adjacent tissues. Furthermore, TUSC3 expression and World Health Organization grade demonstrated an inverse association in patients with glioma. This revealed that lower levels of TUSC3 in gliomas may be associated with a poorly-differentiated (high grade) tumor and thus a higher malignancy. Through the combination of the results of the present study and future research projects, TUSC3 may be a novel grading tool that assists with evaluating tumor malignancy and consequently a more active therapeutic regimen may be used in patients with glioma.

Current therapeutic approaches to diffuse grade II and III gliomas

The 2016 WHO classification of Tumors of the Central Nervous System brought major conceptual and practical changes in the classification of diffuse gliomas, by combining molecular features and histology into 'integrated' diagnoses. In diffuse gliomas, molecular profiling has thus become essential for nosological purposes, as well as to plan adequate treatment strategies and identify patients susceptible of target therapy. WHO grade II (low grade) and grade III (anaplastic) diffuse gliomas form a heterogeneous group of neoplasms, also known as 'lower-grade gliomas', characterized by a wide range of malignant potential. Molecular profile accounts for this biological diversity, and provides an accurate prognostic stratification of tumors in this group. Treatment strategies in lower-grade gliomas are ultimately based on molecular profile and WHO grade, as well as on patient characteristics such as age and Karnofsky performance status. The purpose of this review is to summarize recent advances in the classification of grade II and III gliomas, synthesize current treatment schemes according to molecular profile and describe ongoing research and future perspectives for the use of target therapies.

Associations between prediagnostic blood glucose levels, diabetes, and glioma

Previous literature indicates that pre-diagnostic diabetes and blood glucose levels are inversely related to glioma risk. To replicate these findings and determine whether they could be attributed to excess glucose consumption by the preclinical tumour, we used data from the Apolipoprotein MOrtality RISk (AMORIS) (n = 528,580) and the Metabolic syndrome and Cancer project (Me-Can) cohorts (n = 269,365). We identified individuals who were followed for a maximum of 15 years after their first blood glucose test until glioma diagnosis, death, emigration or the end of follow-up. Hazard ratios (HRs), 95% confidence intervals (CIs) and their interactions with time were estimated using Cox time-dependent regression. As expected, pre-diagnostic blood glucose levels were inversely related to glioma risk (AMORIS, P_trend = 0.002; Me-Can, P_trend = 0.04) and pre-diagnostic diabetes (AMORIS, HR = 0.30, 95% CI 0.17 to 0.53). During the year before diagnosis, blood glucose was inversely associated with glioma in the AMORIS (HR = 0.78, 95% CI 0.66 to 0.93) but not the Me-Can cohort (HR = 0.99, 95% CI 0.63 to 1.56). This AMORIS result is consistent with our hypothesis that excess glucose consumption by the preclinical tumour accounts for the inverse association between blood glucose and glioma. We discuss additional hypothetical mechanisms that may explain our paradoxical findings.