Non-V600 mutations comprise approximately 35% of all BRAF mutations in cancer. Many of these mutations have been identified as oncogenic drivers and can be classified into three classes according to ...molecular characteristics. Consensus treatment strategies for class 2 and 3 BRAF mutations have not yet been established.
We performed a systematic review and meta-analysis with published reports of individual patients with cancer harboring class 2 or 3 BRAF mutations from 2010 to 2021, to assess treatment outcomes with US Food and Drug Administration-approved mitogen-activated protein kinase (MAPK) pathway targeted therapy (MAPK TT) according to BRAF class, cancer type, and MAPK TT type. Coprimary outcomes were response rate and progression-free survival.
A total of 18,167 studies were screened, identifying 80 studies with 238 patients who met inclusion criteria. This included 167 patients with class 2 and 71 patients with class 3 BRAF mutations. Overall, 77 patients achieved a treatment response. In both univariate and multivariable analyses, response rate and progression-free survival were higher among patients with class 2 compared with class 3 mutations, findings that remain when analyses are restricted to patients with melanoma or lung primary cancers. MEK ± BRAF inhibitors demonstrated greater clinical activity in class 2 compared with class 3 BRAF-mutant tumors than BRAF or EGFR inhibitors.
This meta-analysis suggests that MAPK TTs have clinical activity in some class 2 and 3 BRAF-mutant cancers. BRAF class may dictate responsiveness to current and emerging treatment strategies, particularly in melanoma and lung cancers. Together, this analysis provides clinical validation of predictions made on the basis of a mutation classification system established in the preclinical literature. Further evaluation with prospective clinical trials is needed for this population.
Purpose
The purpose of this study was to examine advanced diffusion-weighted magnetic resonance imaging (DW-MRI) models for differentiation of low- and high-grade tumors in the diagnosis of pediatric ...brain neoplasms.
Methods
Sixty-two pediatric patients with various types and grades of brain tumors were evaluated in a retrospective study. Tumor type and grade were classified using the World Health Organization classification (WHO I-IV) and confirmed by pathological analysis. Patients underwent DW-MRI before treatment. Diffusion-weighted images with 16
b
-values (0–3500 s/mm
2
) were acquired. Averaged signal intensity decay within solid tumor regions was fitted using two-compartment and anomalous diffusion models. Intracellular and extracellular diffusion coefficients (D
slow
and D
fast
), fractional volumes (V
slow
and V
fast
), generalized diffusion coefficient (
D
), spatial constant (μ), heterogeneity index (β), and a diffusion index (index_diff = μ × V
slow
/β) were calculated. Multivariate logistic regression models with stepwise model selection algorithm and receiver operating characteristic (ROC) analyses were performed to evaluate the ability of each diffusion parameter to distinguish tumor grade.
Results
Among all parameter combinations,
D
and index_diff jointly provided the best predictor for tumor grades, where lower
D
(
p
= 0.03) and higher index_diff (
p
= 0.009) were significantly associated with higher tumor grades. In ROC analyses of differentiating low-grade (I-II) and high-grade (III-IV) tumors, index_diff provided the highest specificity of 0.97 and
D
provided the highest sensitivity of 0.96.
Conclusions
Multi-parametric diffusion measurements using two-compartment and anomalous diffusion models were found to be significant discriminants of tumor grading in pediatric brain neoplasms.
Treatment of recurrent primary pediatric brain tumors remains a major challenge, with most children succumbing to their disease. We conducted a prospective phase 2 study investigating the safety and ...efficacy of pomalidomide (POM) in children and young adults with recurrent and progressive primary brain tumors.
Patients with recurrent and progressive high-grade glioma (HGG), diffuse intrinsic pontine glioma (DIPG), ependymoma, or medulloblastoma received POM 2.6 mg/m
/day (the recommended phase 2 dose RP2D) on days 1-21 of a 28-day cycle. A Simon's Optimal 2-stage design was used to determine efficacy. Primary endpoints included objective response (OR) and long-term stable disease (LTSD) rates. Secondary endpoints included duration of response, progression-free survival (PFS), overall survival (OS), and safety.
46 patients were evaluable for response (HGG, n = 19; DIPG, ependymoma, and medulloblastoma, n = 9 each). Two patients with HGG achieved OR or LTSD (10.5% 95% CI, 1.3%-33.1%; 1 partial response and 1 LTSD) and 1 patient with ependymoma had LTSD (11.1% 95% CI, 0.3%-48.2%). There were no ORs or LTSD in the DIPG or medulloblastoma cohorts. The median PFS for patients with HGG, DIPG, ependymoma, and medulloblastoma was 7.86, 11.29, 8.43, and 8.43 weeks, respectively. Median OS was 5.06, 3.78, 12.02, and 11.60 months, respectively. Neutropenia was the most common grade 3/4 adverse event.
Treatment with POM monotherapy did not meet the primary measure of success in any cohort. Future studies are needed to evaluate if POM would show efficacy in tumors with specific molecular signatures or in combination with other anticancer agents.
ClinicalTrials.gov, identifier NCT03257631; EudraCT, identifier 2016-002903-25.
Apoptosis is an essential process during normal neuronal development. Approximately one-half of the neurons produced during neurogenesis die before completion of CNS maturation. To characterize the ...role of the inhibitor of apoptosis gene, survivin, during neurogenesis, we used the Cre-loxP-system to generate mice lacking survivin in neuronal precursor cells. Conditional deletion of survivin starting at embryonic day 10.5 leads to massive apoptosis of neuronal precursor cells in the CNS. Conditional mutants were born at the expected Mendelian ratios; however, these died shortly after birth from respiratory insufficiency, without primary cardiopulmonary pathology. Newborn conditional mutants showed a marked reduction in the size of the brain associated with severe, mutifocal apoptosis in the cerebrum, cerebellum, brainstem, spinal cord, and retina. Caspase-3 and caspase-9 activities in the mutant brains were significantly elevated, whereas bax expression was unchanged from controls. These results show that survivin is critically required for the survival of developing CNS neurons, and may impact on our understanding of neural repair, neural development, and neurodegenerative diseases. Our study is the first to solidify a role for survivin as an antiapoptotic protein during normal neuronal development in vivo.
Profiling of pediatric cancers through deep sequencing of large gene panels and whole exomes is rapidly being adopted in many clinical settings. However, the most impactful approach to genomic ...profiling of pediatric cancers remains to be defined.
We conducted a prospective precision medicine trial, using whole-exome sequencing of tumor and germline tissue and whole-transcriptome sequencing (RNA Seq) of tumor tissue to characterize the mutational landscape of 127 tumors from 126 unique patients across the spectrum of pediatric brain tumors, hematologic malignancies, and extracranial solid tumors.
We identified somatic tumor alterations in 121/127 (95.3%) tumor samples and identified cancer predisposition syndromes on the basis of known pathogenic or likely pathogenic germline mutations in cancer predisposition genes in 9/126 patients (7.1%). Additionally, we developed a novel scoring system for measuring the impact of tumor and germline sequencing, encompassing therapeutically relevant genomic alterations, cancer-related germline findings, recommendations for treatment, and refinement of risk stratification or prognosis. At least one impactful finding from the genomic results was identified in 108/127 (85%) samples sequenced. A recommendation to consider a targeted agent was provided for 82/126 (65.1%) patients. Twenty patients ultimately received therapy with a molecularly targeted agent, representing 24% of those who received a targeted agent recommendation and 16% of the total cohort.
Paired tumor/normal whole-exome sequencing and tumor RNA Seq of de novo or relapsed/refractory tumors was feasible and clinically impactful in high-risk pediatric cancer patients.
To assess frequency of neural stem cell compartment (NSC) involvement in adult and pediatric gliomas World Health Organization (WHO) grades 1–4, and to assess whether NSC involvement at presentation ...impacts on survival, recurrence rates, and/or transformation from low grade (WHO grade 1–2) to high grade disease (WHO grades 3–4). Cranial MRIs for 154 pediatric and 223 adult glioma patients treated from 2000 to 2012 were reviewed. NSC involvement was documented. Tumors were stratified by age (adult vs. pediatric), histology, tumor grade, tumor location, and involvement of midline structures. Odds ratios (OR) for death were calculated based on NSC status at presentation. Rates of transformation and recurrence rates (ORR) were compared using Fisher’s Exact Test. Time to recurrence (TTR) was calculated using student
t
test. Among recurrent and transformed tumors, we also assessed the rate of NSC involvement at time of recurrence or transformation. 74.8 % of tumors had NSC involvement. Higher rates of NSC involvement were seen among adult (p = .0001); high grade (p = .0001)); grade 2 versus grade 1 (p = .0001) and other grade 1 histologies (p = .0001) versus JPA (juvenile pilocytic astrocytoma) patients); grade 2–4 tumors (p = .0001); and supratentorial tumors (p < .0001). No transformation was noted among pediatric low grade tumors or adult grade 1 tumors. 22/119 (18.5 %) adult grade 2 tumors transformed. Rates of transformation were not impacted by NSC status (p = .47). ORR was 15.1 %, and was greater for NSC+ tumors at presentation (p = .05). 36/41 recurrences (87.8 %) involved NSC at time of recurrence. OR for death was 2.62 (1.16–5.9), p = .02 for NSC+ tumors at presentation. Adult and pediatric gliomas (all grades) frequently involve NSC at presentation, although rates are lower in pediatric JPA and all infratentorial tumors. NSC involvement at presentation increases OR death and reduces TTR for pediatric gliomas (all grades) and adult low grade gliomas, and shows a strong trend toward increased ORR.
Management of pediatric low-grade glioma de Blank, Peter; Bandopadhayay, Pratiti; Haas-Kogan, Daphne ...
Current opinion in pediatrics,
02/2019, Letnik:
31, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Pediatric low-grade gliomas (pLGGs) have been treated with similar therapies for the last 30 years. Recent biological insights have allowed a new generation of targeted therapies to be developed for ...these diverse tumors. At the same time, technological advances may redefine the late toxicities associated with radiation therapy. Understanding recent developments in pLGG therapy is essential to the management of these common pediatric tumors.
It is now well understood that aberrations of the mitogen-activated protein kinase pathway are key to oncogenesis in low-grade gliomas. This understanding, along with the development of available targeted agents, have heralded a new era of understanding and treatment for these patients. Promising, sustained responses are now being seen in early phase trials among patients with multiply recurrent/progressive disease. Also, newer and highly conformal radiation approaches such as proton beam radiotherapy maintain efficacy of radiation but limit radiation-associated toxicities.
Novel therapies offer the potential for tumor control with greatly reduced toxicities. However, late effects of these therapies are just now being explored. Improved radiation approaches and targeted agents have the potential to redefine traditional therapy for pLGG.
Genetic syndromes which develop one or more nervous system (NS) tumors as one of the manifestations can be grouped under the umbrella term of NS tumor predisposition syndromes. Understanding the ...underlying pathological pathways at the molecular level has led us to many radical discoveries, in understanding the mechanisms of tumorigenesis, tumor progression, interactions with the tumor microenvironment, and development of targeted therapies. Currently, at least 7–10% of all pediatric cancers are now recognized to occur in the setting of genetic predisposition to cancer or cancer predisposition syndromes. Specifically, the cancer predisposition rate in pediatric patients with NS tumors has been reported to be as high as 15%, though it can approach 50% in certain tumor types (i.e., choroid plexus carcinoma associated with Li Fraumeni Syndrome). Cancer predisposition syndromes are caused by pathogenic variation in genes that primarily function as tumor suppressors and proto-oncogenes. These variants are found in the germline or constitutional DNA. Mosaicism, however, can affect only certain tissues, resulting in varied manifestations. Increased understanding of the genetic underpinnings of cancer predisposition syndromes and the ability of clinical laboratories to offer molecular genetic testing allows for improvement in the identification of these patients. The identification of a cancer predisposition syndrome in a CNS tumor patient allows for changes to medical management to be made, including the initiation of cancer surveillance protocols. Finally, the identification of at-risk biologic relatives becomes feasible through cascade (genetic) testing. These fundamental discoveries have also broadened the horizon of novel therapeutic possibilities and have helped to be better predictors of prognosis and survival. The treatment paradigm of specific NS tumors may also vary based on the patient’s cancer predisposition syndrome and may be used to guide therapy (i.e., immune checkpoint inhibitors in constitutional mismatch repair deficiency CMMRD predisposition syndrome) 8. Early diagnosis of these cancer predisposition syndromes is therefore critical, in both unaffected and affected patients. Genetic counselors are uniquely trained master’s level healthcare providers with a focus on the identification of hereditary disorders, including hereditary cancer, or cancer predisposition syndromes. Genetic counseling, defined as “the process of helping people understand and adapt to the medical, psychological and familial implications of genetic contributions to disease” plays a vital role in the adaptation to a genetic diagnosis and the overall management of these diseases. Cancer predisposition syndromes that increase risks for NS tumor development in childhood include classic neurocutaneous disorders like neurofibromatosis type 1 and type 2 (NF1, NF2) and tuberous sclerosis complex (TSC) type 1 and 2 (TSC1, TSC2). Li Fraumeni Syndrome, Constitutional Mismatch Repair Deficiency, Gorlin syndrome (Nevoid Basal Cell Carcinoma), Rhabdoid Tumor Predisposition syndrome, and Von Hippel-Lindau disease. Ataxia Telangiectasia will also be discussed given the profound neurological manifestations of this syndrome. In addition, there are other cancer predisposition syndromes like Cowden/PTEN Hamartoma Tumor Syndrome, DICER1 syndrome, among many others which also increase the risk of NS neoplasia and are briefly described. Herein, we discuss the NS tumor spectrum seen in the abovementioned cancer predisposition syndromes as with their respective germline genetic abnormalities and recommended surveillance guidelines when applicable. We conclude with a discussion of the importance and rationale for genetic counseling in these patients and their families.
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