Existing drug delivery methods have not led to a significant increase in survival for patients with malignant primary brain tumors. While the combination of conventional therapies consisting of ...surgery, radiotherapy, and chemotherapy has improved survival for some types of brain tumors (e.g., WNT medulloblastoma), other types of brain tumors (e.g., glioblastoma and diffuse midline glioma) still have a poor prognosis. The reason for the differences in response can be largely attributed to the blood–brain barrier (BBB), a specialized structure at the microvasculature level that regulates the transport of molecules across the blood vessels into the brain parenchyma. This structure hampers the delivery of most chemotherapeutic agents for the treatment of primary brain tumors. Several drug delivery methods such as nanoparticles, convection enhanced delivery, focused ultrasound, intranasal delivery, and intra-arterial delivery have been developed to overcome the BBB in primary brain tumors. However, prognosis of most primary brain tumors still remains poor. The heterogeneity of the BBB in primary brain tumors and the distinct vasculature of tumors make it difficult to design a drug delivery method that targets the entire tumor. Drug delivery methods that combine strategies such as focused ultrasound and nanoparticles might be a more successful approach. However, more research is needed to optimize and develop new drug delivery techniques to improve survival of patients with primary brain tumors.
While RB1 loss initiates retinoblastoma development, additional somatic copy number alterations (SCNAs) can drive tumor progression. Although SCNAs have been identified with good concordance between ...studies at a cytoband resolution, accurate identification of single genes for all recurrent SCNAs is still challenging. This study presents a comprehensive meta-analysis of genome-wide SCNAs integrated with gene expression profiling data, narrowing down the list of plausible retinoblastoma driver genes.
We performed SCNA profiling of 45 primary retinoblastoma samples and eight retinoblastoma cell lines by high-resolution microarrays. We combined our data with genomic, clinical and histopathological data of ten published genome-wide SCNA studies, which strongly enhanced the power of our analyses (N = 310).
Comprehensive recurrence analysis of SCNAs in all studies integrated with gene expression data allowed us to reduce candidate gene lists for 1q, 2p, 6p, 7q and 13q to a limited gene set. Besides the well-established driver genes RB1 (13q-loss) and MYCN (2p-gain) we identified CRB1 and NEK7 (1q-gain), SOX4 (6p-gain) and NUP205 (7q-gain) as novel retinoblastoma driver candidates. Depending on the sample subset and algorithms used, alternative candidates were identified including MIR181 (1q-gain) and DEK (6p gain). Remarkably, our study showed that copy number gains rarely exceeded change of one copy, even in pure tumor samples with 100% homozygosity at the RB1 locus (N = 34), which is indicative for intra-tumor heterogeneity. In addition, profound between-tumor variability was observed that was associated with age at diagnosis and differentiation grades.
Since focal alterations at commonly altered chromosome regions were rare except for 2p24.3 (MYCN), further functional validation of the oncogenic potential of the described candidate genes is now required. For further investigations, our study provides a refined and revised set of candidate retinoblastoma driver genes.
Despite major improvements in outcome over the past decades, acute myeloid leukemia (AML) remains a life-threatening malignancy in children, with current survival rates of ∼ 70%. State-of-the-art ...recommendations in adult AML have recently been published in this journal by Döhner et al. The primary goal of an international expert panel of the International BFM Study Group AML Committee was to set standards for the management, diagnosis, response assessment, and treatment in childhood AML. This paper aims to discuss differences between childhood and adult AML, and to highlight recommendations that are specific to children. The particular relevance of new diagnostic and prognostic molecular markers in pediatric AML is presented. The general management of pediatric AML, the management of specific pediatric AML cohorts (such as infants) or subtypes of the disease occurring in children (such as Down syndrome related AML), as well as new therapeutic approaches, and the role of supportive care are discussed.
Alternative splicing is a tightly regulated process whereby non-coding sequences of pre-mRNA are removed and protein-coding segments are assembled in diverse combinations, ultimately giving rise to ...proteins with distinct or even opposing functions. In the past decade, whole genome/transcriptome sequencing studies revealed the high complexity of splicing regulation, which occurs co-transcriptionally and is influenced by chromatin status and mRNA modifications. Consequently, splicing profiles of both healthy and malignant cells display high diversity and alternative splicing was shown to be widely deregulated in multiple cancer types. In particular, mutations in pre-mRNA regulatory sequences, splicing regulators and chromatin modifiers, as well as differential expression of splicing factors are important contributors to cancer pathogenesis. It has become clear that these aberrations contribute to many facets of cancer, including oncogenic transformation, cancer progression, response to anticancer drug treatment as well as resistance to therapy. In this respect, alternative splicing was shown to perturb the expression a broad spectrum of relevant genes involved in drug uptake/metabolism (i.e. SLC29A1, dCK, FPGS, and TP), activation of nuclear receptor pathways (i.e. GR, AR), regulation of apoptosis (i.e. MCL1, BCL-X, and FAS) and modulation of response to immunotherapy (CD19). Furthermore, aberrant splicing constitutes an important source of novel cancer biomarkers and the spliceosome machinery represents an attractive target for a novel and rapidly expanding class of therapeutic agents. Small molecule inhibitors targeting SF3B1 or splice factor kinases were highly cytotoxic against a wide range of cancer models, including drug-resistant cells. Importantly, these effects are enhanced in specific cancer subsets, such as splicing factor-mutated and c-MYC-driven tumors. Furthermore, pre-clinical studies report synergistic effects of spliceosome modulators in combination with conventional antitumor agents. These strategies based on the use of low dose splicing modulators could shift the therapeutic window towards decreased toxicity in healthy tissues. Here we provide an extensive overview of the latest findings in the field of regulation of splicing in cancer, including molecular mechanisms by which cancer cells harness alternative splicing to drive oncogenesis and evade anticancer drug treatment as well as splicing-based vulnerabilities that can provide novel treatment opportunities. Furthermore, we discuss current challenges arising from genome-wide detection and prediction methods of aberrant splicing, as well as unravelling functional relevance of the plethora of cancer-related splicing alterations.
Treatment outcomes for pediatric patients with acute myeloid leukemia (AML) have continued to lag behind outcomes reported for children with acute lymphoblastic leukemia (ALL), in part because of the ...heterogeneity of the disease, a paucity of targeted therapies, and the relatively slow development of immunotherapy compared with ALL. In addition, we have reached the limits of treatment intensity, and, even with outstanding supportive care, it is highly unlikely that further intensification of conventional chemotherapy alone will impact relapse rates. However, comprehensive genomic analyses and a more thorough characterization of the leukemic stem cell have provided insights that should lead to tailored and more effective therapies in the near future. In addition, new therapies are finally emerging, including the BCL-2 inhibitor venetoclax, CD33- and CD123-directed chimeric antigen receptor T-cell therapy, CD123-directed antibody therapy, and menin inhibitors. Here, we present 4 cases to illustrate some of the controversies regarding the optimal treatment of children with newly diagnosed or relapsed AML.
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Background
A decreased physical fitness has been reported in patients and survivors of childhood cancer. This is influenced by the negative effects of the disease and the treatment of childhood ...cancer. Exercise training for adult cancer patients has frequently been reported to improve physical fitness. In recent years, literature on this subject has also become available for children and young adults with cancer, both during and after treatment. This is an update of the original review that was performed in 2011.
Objectives
To evaluate the effect of a physical exercise training intervention on the physical fitness (i.e. aerobic capacity, muscle strength, or functional performance) of children with cancer within the first five years from their diagnosis (performed either during or after cancer treatment), compared to a control group of children with cancer who did not receive an exercise intervention.
To determine whether physical exercise within the first five years of diagnosis has an effect on fatigue, anxiety, depression, self efficacy, and HRQoL and to determine whether there are any adverse effects of the intervention.
Search methods
We searched the electronic databases of Cochrane Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, and PEDro; ongoing trial registries and conference proceedings on 6 September 2011 and 11 November 2014. In addition, we performed a handsearch of reference lists.
Selection criteria
The review included randomized controlled trials (RCTs) and clinical controlled trials (CCTs) that compared the effects of physical exercise training with no training, in people who were within the first five years of their diagnosis of childhood cancer.
Data collection and analysis
Two review authors independently identified studies meeting the inclusion criteria, performed the data extraction, and assessed the risk of bias using standardized forms. Study quality was rated by the Grading of Recommendation Assessment, Development and Evaluation (GRADE) criteria.
Main results
Apart from the five studies in the original review, this update included one additional RCT. In total, the analysis included 171 participants, all during treatment for childhood acute lymphoblastic leukaemia (ALL).
The duration of the training sessions ranged from 15 to 60 minutes per session. Both the type of intervention and intervention period varied in all the included studies. However, the control group always received usual care.
All studies had methodological limitations, such as small numbers of participants, unclear randomization methods, and single‐blind study designs in case of one RCT and all results were of moderate to very low quality (GRADE).
Cardiorespiratory fitness was evaluated by the 9‐minute run‐walk test, timed up‐and‐down stairs test, the timed up‐and‐go time test, and the 20‐m shuttle run test. Data of the 9‐minute run‐walk test and the timed up‐and‐down stairs test could be pooled. The combined 9‐minute run‐walk test results showed significant differences between the intervention and the control groups, in favour of the intervention group (standardized mean difference (SMD) 0.69; 95% confidence interval (CI) 0.02 to 1.35). Pooled data from the timed up‐and‐down stairs test showed no significant differences in cardiorespiratory fitness (SMD ‐0.54; 95% CI ‐1.77 to 0.70). However, there was considerable heterogeneity (I2 = 84%) between the two studies on this outcome. The other two single‐study outcomes, 20‐m shuttle run test and the timed up‐and‐go test, also showed positive results for cardiorespiratory fitness in favour of the intervention group.
Only one study assessed the effect of exercise on bone mineral density (total body), showing a statistically significant positive intervention effect (SMD 1.07; 95% CI 0.48 to 1.66). The pooled data on body mass index showed no statistically significant end‐score difference between the intervention and control group (SMD 0.59; 95% CI ‐0.23 to 1.41).
Three studies assessed flexibility. Two studies assessed ankle dorsiflexion. One study assessed active ankle dorsiflexion, while the other assessed passive ankle dorsiflexion. There were no statistically significant differences between the intervention and control group with the active ankle dorsiflexion test; however, in favour of the intervention group, they were found for passive ankle dorsiflexion (SMD 0.69; 95% CI 0.12 to 1.25). The third study assessed body flexibility using the sit‐and‐reach distance test, but identified no statistically significant difference between the intervention and control group.
Three studies assessed muscle strength (knee, ankle, back and leg, and inspiratory muscle strength). Only the back and leg strength combination score showed statistically significant differences on the muscle strength end‐score between the intervention and control group (SMD 1.41; 95% CI 0.71 to 2.11).
Apart from one sub‐scale of the cancer scale (Worries; P value = 0.03), none of the health‐related quality of life scales showed a significant difference between both study groups on the end‐score. For the other outcomes of fatigue, level of daily activity, and adverse events (all assessed in one study), there were no statistically significant differences between the intervention and control group.
None of the included studies evaluated activity energy expenditure, time spent on exercise, anxiety and depression, or self efficacy as an outcome.
Authors' conclusions
The effects of physical exercise training interventions for childhood cancer participants are not yet convincing. Possible reasons are the small numbers of participants and insufficient study designs, but it can also be that this type of intervention is not as effective as in adult cancer patients. However, the first results show some positive effects on physical fitness in the intervention group compared to the control group. There were positive intervention effects for body composition, flexibility, cardiorespiratory fitness, muscle strength, and health‐related quality of life (cancer‐related items). These were measured by some assessment methods, but not all. However, the quality of the evidence was low and these positive effects were not found for the other assessed outcomes, such as fatigue, level of daily activity, and adverse events. There is a need for more studies with comparable aims and interventions, using a higher number of participants that also include diagnoses other than ALL.
Highlights • Childhood cancer survivors are at risk for reduced ovarian function after high doses of alkylating agents and with older age at diagnosis. • Important risk factors for ovarian ...dysfunction were use of alkylating agents, specifically procarbazine and busulfan, and older age at treatment. • It is imperative that nation-wide registries guarantee long term follow-up during the adult life of cancer survivors.
Abstract Over the past decade, the proteasome inhibitor bortezomib (Velcade) has not only gained a cornerstone position in the treatment of hematological malignancies, particularly multiple myeloma ...and mantle cell lymphoma, but also in experimental therapeutics of acute leukemia. However, the therapeutic efficacy of bortezomib is hampered by the emergence of acquired resistance, for which multifactorial mechanisms have been identified. This review summarizes the current status of the molecular mechanisms underlying resistance to proteasome inhibitors that emerged in preclinical therapeutic studies, and discusses these findings in the clinical perspective of novel therapeutic modalities of hematological malignancies. The specific topics that will be addressed in the current review include the recently established mechanisms of resistance to proteasome inhibitors: the role of constitutive and immunoproteasomes, mutations in proteasome subunits, unfolded protein response, XBP1 and MARCKS proteins, multidrug efflux transporters, aggresomes and autophagy, as well as the impact of pro-survival signaling pathways and bone marrow microenvironment. The growing knowledge of the determinants that confer bortezomib resistance and/or toxicity has provided the basis for the rational development of second generation proteasome inhibitors, some of which were recently approved or that are undergoing clinical evaluation as novel strategies to overcome bortezomib resistance as well as to enhance clinical therapeutic efficacy along with minimal side effects. Collectively, these combined approaches should enhance therapeutic efficacy and outcome in patients with hematological malignancies.
Translocations involving chromosome 11q23 frequently occur in pediatric acute myeloid leukemia (AML) and are associated with poor prognosis. In most cases, the MLL gene is involved, and more than 50 ...translocation partners have been described. Clinical outcome data of the 11q23-rearranged subgroups are scarce because most 11q23 series are too small for meaningful analysis of subgroups, although some studies suggest that patients with t(9;11)(p22;q23) have a more favorable prognosis. We retrospectively collected outcome data of 756 children with 11q23- or MLL-rearranged AML from 11 collaborative groups to identify differences in outcome based on translocation partners. All karyotypes were centrally reviewed before assigning patients to subgroups. The event-free survival of 11q23/MLL-rearranged pediatric AML at 5 years from diagnosis was 44% (± 5%), with large differences across subgroups (11% ± 5% to 92% ± 5%). Multivariate analysis identified the following subgroups as independent prognostic predictors: t(1;11)(q21;q23) (hazard ratio HR = 0.1, P = .004); t(6;11)(q27;q23) (HR = 2.2, P < .001); t(10;11)(p12;q23) (HR = 1.5, P = .005); and t(10;11)(p11.2;q23) (HR = 2.5, P = .005). We could not confirm the favorable prognosis of the t(9;11)(p22;q23) subgroup. We identified large differences in outcome within 11q23/MLL-rearranged pediatric AML and novel subgroups based on translocation partners that independently predict clinical outcome. Screening for these translocation partners is needed for accurate treatment stratification at diagnosis.
A decreased physical fitness and impaired social functioning has been reported in patients and survivors of childhood cancer. This is influenced by the negative effects of disease and treatment of ...childhood cancer and by behavioural and social elements. Exercise training for adults during or after cancer therapy has frequently been reported to improve physical fitness and social functioning. More recently, literature on this subject became available for children and young adults with cancer, both during and after treatment.
This review aimed to evaluate the effect of a physical exercise training intervention (at home, at a physical therapy centre, or hospital based) on the physical fitness of children with cancer, in comparison with the physical fitness in a care as usual control group. The intervention needed to be offered within the first five years from diagnosis.The second aim was to assess the effects of a physical exercise training intervention in this population on fatigue, anxiety, depression, self efficacy, and health-related quality of life and to assess the adverse effects of the intervention.
For this review the electronic databases of CENTRAL, MEDLINE, EMBASE, CINAHL, PEDro, and ongoing trial registries were searched on 6 September 2011. In addition, a handsearch of reference lists and conference proceedings was performed in that same month.
The review included randomised controlled trials (RCTs) and clinical controlled trials (CCTs) that compared the effects of physical exercise training with no training, in people who were within the first five years of their diagnosis of childhood cancer.
By the use of standardised forms two review authors independently identified studies meeting the inclusion criteria, performed the data extraction, and assessed the risk of bias. Quality of the studies was rated by using the Grading of Recommendation Assessment, Development and Evaluation (GRADE) criteria.
Five articles were included in this review: four RCTs (14, 14, 28, and 51 participants) and one CCT (24 participants). In total 131 participants (74 boys, 54 girls, three unknown) were included in the analysis, all being treated for childhood acute lymphoblastic leukaemia (ALL). The study interventions were all implemented during chemotherapy treatment.The duration of the training sessions ranged from 15 to 60 minutes per session. Both the type of intervention, as well as the intervention period, which ranged from 10 weeks to two years, varied in all the included studies. In all included studies the control group received care as usual.All studies had methodological limitations, such as small numbers of participants, unclear randomisation methods, and single-blind study designs in case of an RCT.Cardiorespiratory fitness was studied by the use of the nine-minute run-walk test, the timed up-and-down stairs test, and the 20-m shuttle run test. Only the up-and-down stairs test showed significant differences between the intervention and the control group, in favour of the intervention group (P value = 0.05, no further information available).Bone mineral density was assessed in one study, in which a statistically significant difference in favour of the exercise group was identified (standardised mean difference (SMD) 1.07; 95% confidence interval (CI) 0.48 to 1.66; P value < 0.001). Body mass index was assessed in two studies. The pooled data on this item did not show a statistically significant difference between the intervention and control study group.Flexibility was assessed in three studies. In one study the active ankle dorsiflexion method was used to assess flexibility and the second study they used the passive ankle dorsiflexion test. No statistically significant difference between the intervention and control group was identified with the active ankle dorsiflexion test, whereas with the passive test method a statistically significant difference in favour of the exercise group was found (SMD 0.69; 95% CI 0.12 to 1.25; P value = 0.02). The third study assessed body flexibility by the use of the sit-and-reach distance test; no statistically significant difference between the intervention and control group was identified.One study assessed the effects of an inspiratory muscle training programme aimed to train the lung muscles and increase physical fitness. This study reported no significant effect on either inspiratory or expiratory muscle strength. Two other studies using either knee and ankle strength changes by hand-held dynamometry or the number of completed push-ups (with knees on the ground) and a peripheral quantitative computed tomography of the tibia to determine the muscle mass did not identify statistically significant differences in muscle strength/endurance.The level of daily activity, health-related quality of life, fatigue, and adverse events were assessed in one study only; for all these items no statistically significant differences between the intervention and control group were found.None of the included studies evaluated the outcomes activity energy expenditure, time spent exercising, anxiety and depression, or self efficacy.
The effects of physical exercise training interventions for childhood cancer participants are not yet convincing due to small numbers of participants and insufficient study methodology. Despite that, first results show a trend towards an improved physical fitness in the intervention group compared to the control group. Changes in physical fitness were seen by improved body composition, flexibility, and cardiorespiratory fitness. However, the evidence is limited and these positive effects were not found for the other assessed outcomes, such as muscle strength/endurance, the level of daily activity, health-related quality of life, and fatigue. There is a need for more studies with comparable aims and interventions, using higher numbers of participants and for studies with another childhood cancer population than ALL only.
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