Survival analysis and prognostic factors in posterior fossa ependymomas in children and adolescents.

OBJECTIVE: In this study, the authors aimed to analyze the overall survival (OS) and progression-free survival (PFS) of patients younger than 18 years of age who were diagnosed with posterior fossa ependymomas, and to identify prognostic factors such as the degree of resection, tumor topography, and involvement of the lesion in the hindbrain. METHODS: The authors performed a retrospective cohort study of patients younger than 18 years of age, treated beginning in 2000, with a diagnosis of posterior fossa ependymoma. Ependymomas were separated into three groups: tumors restricted to the fourth ventricle, tumors inside the fourth ventricle and exiting from the foramen of Luschka, and tumors inside the fourth ventricle and completely surrounding the hindbrain. Furthermore, the tumors were classified by molecular group using the staining method for H3K27me3. Statistical analysis was performed using Kaplan-Meier survival curves, with p < 0.05 considered statistically significant. RESULTS: Of 1693 patients who underwent surgical treatment between January 2000 and May 2021, 55 patients who met the inclusion criteria were included. The median age at diagnosis was 2.98 years. The median OS was 44 months, and the survival rates at 1, 5, and 10 years were 92.5%, 49.1%, and 38.3%, respectively. The cases were assigned to two posterior fossa ependymoma molecular groups: 35 (63.6%) cases to group A and 8 (14.5%) to group B. The median ages in groups A and B were 2.94 and 2.85 years and the median OS values were 44 and 38 months, respectively (p = 0.9245). Statistical analysis was performed on multiple variables, including age, sex, histological grade, Ki-67 expression, tumor volume, extent of resection, and adjuvant therapies. The median PFS of patients with dorsal-only involvement was 28 months; for dorsolateral involvement, it was 15 months; and for total involvement, it was 9.5 months (p = 0.0464). No statistically significant difference was found for OS. There was a statistically significant difference between the proportion of patients in whom gross-total resection was achieved in the dorsal-only involvement group (73.1%, 19/26) and those in the total involvement group (0%, 0/6) (p = 0.0019). CONCLUSIONS: This study confirmed that the extent of resection has an impact on OS and PFS. The authors found that adjuvant radiotherapy resulted in a higher OS but did not prevent progression, that the pattern of involvement of the brainstem in the tumor at diagnosis could elicit important information regarding the patient's prognosis regarding PFS, and that the total involvement of the rhombencephalon impaired the gross-total resection of these tumors.

Quantitative expression evaluation of PRAME gene in osteosarcoma.

BACKGROUND: In a previous study, our group observed that 68% of the osteosarcoma (OS) samples presented PRAME (Preferentially Expressed Antigen in Melanoma) gene expression. In this work, we propose to investigate quantitatively gene expression of PRAME in distinct patients groups. METHODS AND RESULTS: 61 osteosarcoma samples, from 3 distinct patients groups were selected for this study: (1) Patients younger than 10 years old at diagnosis, (2) Patients that had poor evolution of disease and (3) Patients that were in remission of disease and had treatment with no intercurrences) PRAME gene expression levels were obtained using quantitative Real-Time Polymerase Chain Reaction method (qRT-PCR). Clinical parameters were collected from patient's medical charts. Results demonstrated an increase in PRAME gene expression in all samples, with high variation in expression levels, when considering all samples and when analyzed in each group. In addition, no statistical difference was found when considering clinical data collected or patients groups. CONCLUSION: PRAME gene expression quantitative investigation did not bring any complementary information beyond of what had already been observed in other qualitative investigations published by our group, there is no relation between PRAME gene expression levels and disease evolution. However, the findings in this work contribute for validation PRAME gene expression as a good biomarker to OS, which, in the future, may allow identification circulating tumor cell or molecules to contribute with early diagnostic of metastasis, a genuine problem in OS that determinate flattening in survival curves.

Gliomas in children and adolescents: investigation of molecular alterations with a potential prognostic and therapeutic impact.

PURPOSE: Gliomas represent the most frequent central nervous system (CNS) tumors in children and adolescents. However, therapeutic strategies for these patients, based on tumor molecular profile, are still limited compared to the wide range of treatment options for the adult population. We investigated molecular alterations, with a potential prognostic marker and therapeutic target in gliomas of childhood and adolescence using the next-generation sequencing (NGS) strategy. METHODS: We selected 95 samples with initial diagnosis of glioma from patients treated at Pediatric Oncology Institute-GRAACC/UNIFESP. All samples were categorized according to the 2021 World Health Organization Classification of Tumors of the CNS, which included 39 low-grade gliomas (LGGs) and 56 high-grade gliomas (HGGs). Four HGG samples were classified as congenital glioblastoma (cGBM). NGS was performed to identify somatic genetic variants in tumor samples using the Oncomine Childhood Cancer Research Assay® (OCCRA®) panel, from Thermo Fisher Scientific®. RESULTS: Genetic variants were identified in 76 of 95 (80%) tumors. In HGGs, the most common molecular alteration detected was H3F3A c.83A > T variant (H3.3 K27M) and co-occurring mutations in ATRX, TP53, PDGFRA, MET, and MYC genes were also frequently observed. One HGG sample was reclassified as supratentorial ependymoma ZFTA-fusion positive after NGS was performed. In LGGs, four KIAA1549-BRAF fusion transcripts were detected and this alteration was the most recurrent genetic event and favorable prognostic factor identified. Additionally, genetic variants in ALK and NTRK genes, which provide potential targets for therapy with Food and Drug Administration-approved drugs, were identified in two different cases of cGBM that were classified as infant-type hemispheric glioma, a newly recognized subgroup of pediatric HGG. CONCLUSION: Molecular profiling by the OCCRA® panel comprehensively addressed the most relevant genetic variants in gliomas of childhood and adolescence, as these tumors have specific patterns of molecular alterations, outcomes, and effectiveness to therapies.

Molecular profiling of pediatric and adolescent ependymomas: identification of genetic variants using a next-generation sequencing panel.

PURPOSE: Ependymoma (EPN) accounts for approximately 10% of all primary central nervous system (CNS) tumors in children and in most cases, chemotherapy is ineffective and treatment remains challenging. We investigated molecular alterations, with a potential prognostic marker and therapeutic target in EPNs of childhood and adolescence, using a next-generation sequencing (NGS) panel specific for pediatric neoplasms. METHODS: We selected 61 samples with initial diagnosis of EPN from patients treated at Pediatric Oncology Institute-GRAACC/UNIFESP. All samples were divided according to the anatomical compartment of the CNS - 42 posterior fossa (PF), 14 supratentorial (ST), and five spinal (SP). NGS was performed to identify somatic genetic variants in tumor samples using the Oncomine Childhood Cancer Research Assay® (OCCRA®) panel, from Thermo Fisher Scientific®. RESULTS: Genetic variants were identified in 24 of 61 (39.3%) tumors and over 90% of all variants were pathogenic or likely pathogenic. The most commonly variants detected were in CIC, ASXL1, and JAK2 genes and have not been reported in EPN yet. MN1-BEND2 fusion, alteration recently described in a new CNS tumor type, was identified in one ST sample that was reclassified as astroblastoma. Additionally, YAP1-MAMLD1 fusion, a rare event associated with good outcome in ST-EPN, was observed in two patients diagnosed under 2 years old. CONCLUSIONS: Molecular profiling by the OCCRA® panel showed novel alterations in pediatric and adolescent EPNs, which highlights the clinical importance in identifying genetic variants for patients' prognosis and therapeutic orientation.

Management of Pediatric Tumors With Vascular Extension.

Background: Pediatric tumors can present with vascular extension to the inferior vena cava and right atrium, which impacts the surgical strategy and can be challenging during surgical treatment. Wilms tumor (WT) is the most common retroperitoneal tumor that can present with vascular extension, but also adrenal tumors, clear cell tumors from the kidney, and hepatoblastomas can present with this situation. Surgical aims include obtaining complete tumor resection without risk for patients, to avoid severe bleeding, cardiac arrest, and embolization, and to avoid cardiac bypass if possible. Objective: To describe and discuss the surgical strategies to deal with pediatric tumors with vascular extension and propose a protocol. Method: Retrospectivly review the experience of treating patients with vascular extension in a single institution, describing different scenarios and a decision making fluxogram based on the preoperative evaluation regarding the surgical techniques and the need for cardiac bypass that are adequate for each situation. Image studies are important to guide the surgical strategy. Depending on the quality of image available, computerized tomography (CT) or magnetic resonance imaging (MRI) can be enough to give the information needed for surgical decisions. Ultrasonography (US) with Doppler is helpful to confirm diagnosis and describes factors to guide the adequate surgical strategy, like the upper level extension and presence or absence of blood flow around the thrombus. Neoadjuvant chemotherapy is indicated in most cases, in order to reduce the upper level of extension (and avoid the need for cardiac bypass) and to lower the risk of embolization. The approach is based on the upper level of the thrombus and can include cavotomy or cavectomy, sometimes with cardiac bypass and cardiac arrest with hypothermia, when the thrombus reaches the diaphragmatic level or above. Pathology analysis of the thrombus can guide staging and the need for radiotherapy postoperatively. Results: A decision making fluxogram protocol is presented focusing on the surgical treatment of such condition. Conclusion: Surgery strategy is highly impacted by the presence of vascular extension in pediatric tumors. Surgeons should be aware of potential complications and how to prevent them. Such cases should be treated in reference centers.

Abnormal spindle-like microcephaly-associated (ASPM) gene expression in posterior fossa brain tumors of childhood and adolescence.

PURPOSE: In neurogenesis, ASPM (abnormal spindle-like microcephaly-associated) gene is expressed mainly in the ventricular zone of posterior fossa and is the major determinant in the cerebral cortex. Besides its role in embryonic development, ASPM overexpression promotes tumor growth, including central nervous system (CNS) tumors. This study aims to investigate ASPM expression levels in most frequent posterior fossa brain tumors of childhood and adolescence: medulloblastoma (MB), ependymoma (EPN), and astrocytoma (AS), correlating them with clinicopathological characteristics and tumor solid portion size. METHODS: Quantitative reverse transcription (qRT-PCR) is used to quantify ASPM mRNA levels in 80 pre-treatment tumor samples: 28 MB, 22 EPN, and 30 AS. The tumor solid portion size was determined by IOP-GRAACC Diagnostic Imaging Center. We correlated these findings with clinicopathological characteristics and tumor solid portion size. RESULTS: Our results demonstrated that ASPM gene was overexpressed in MB (p = 0.007) and EPN (p = 0.0260) samples. ASPM high expression was significantly associated to MB samples from patients with worse overall survival (p = 0.0123) and death due to disease progression (p = 0.0039). Interestingly, two patients with AS progressed toward higher grade showed ASPM overexpression (p = 0.0046). No correlation was found between the tumor solid portion size and ASPM expression levels in MB (p = 0.1154 and r = - 0.4825) and EPN (p = 0.1108 and r = - 0.3495) samples. CONCLUSION: Taking in account that ASPM gene has several functions to support cell proliferation, as mitotic defects and premature differentiation, we suggest that its overexpression, presumably, plays a critical role in disease progression of posterior fossa brain tumors of childhood and adolescence.

The impact of burial period on compact bone microstructure: Histological analysis of matrix loss and cell integrity in human bones exhumed from tropical soil.

Human bone histological analysis is a useful tool to assess post mortem diagenesis and to predict successful nuclear DNA typing of forensic material. This study is part of a series of studies developed by the authors intended to improve the understanding of post mortem diagenesis and to develop applications for DNA analysis of skeletal species from tropical soils, in order to optimize genetic and anthropological protocols. The aim of this study was to analyze the impact of burial period on the integrity of exhumed compact bone microstructure from tropical climate. In fragments of exhumed human femora from 39 individuals from the same cemetery (exhumed group) and 5 fresh femora from routine autopsies (control group), sections stained by hematoxylin-eosin were analyzed in order to measure bone microstructural integrity. We found that bone integrity index in exhumed group was negatively influenced by the period of burial (r = -0.37, p < 0.05) and highly significantly decreased (p < 0.0001) in comparison to control group. The period of burial and nitric acid decalcification time was positively correlated (r = 0.51; p < 0.01), leading to imply a bone petrification process during inhumation. Exhumed group showed higher level of matrix bone loss (p < 0.001), as expected, and 87% of cases analyzed were "tunneled" as described by Hackett. Bone integrity index and bone matrix tend to decrease in bones buried in tropical soil between 8-14 years of inhumation. This period is short if we consider cases in which there are preserved bones interred for longer periods in other environments. These data must be considered in cases where genetic identification of exhumed skeletons from tropical environment is required. The diagenesis in these bones and the variations of results found are discussed, clarifying some challenges for forensic laboratories, especially in DNA analysis.

Irinotecan and vincristine for the treatment of refractory desmoplastic small round cell tumor in a developing country: a case report.

INTRODUCTION: Desmoplastic small round cell tumor is an extremely rare and aggressive cancer that affects mainly adolescents and young adults. Despite multiple therapeutic strategies, most patients have resistant disease with very poor survival rates. CASE PRESENTATION: We present a case of a 10-year-old Caucasian boy with a desmoplastic small round cell tumor refractory to conventional treatment who exhibited a good response to alternative treatment. With use of irinotecan and vincristine in association with radiation therapy, a reduction of 96.9% of the dimensions of the target lesions compared with the initial image was observed. CONCLUSION: This chemotherapy regimen, in association with radiation therapy, demonstrated efficacy for refractory desmoplastic small round cell tumor in our patient, and it is cost-effective.

Epigenetic regulation of metalloproteinases and their inhibitors in rotator cuff tears.

Rotator cuff tear is a common orthopedic condition. Metalloproteinases (MMP) and their inhibitors (TIMP) seem to play a role in the development of joint injuries and in the failure of tissue healing. However, the mechanisms of regulation of gene expression in tendons are still unknown. Epigenetic mechanisms, such as DNA methylation and microRNAs regulation, are involved in the dynamic control of gene expression. Here, the mRNA expression and DNA methylation status of MMPs (MMP1, MMP2, MMP3, MMP9, MMP13, and MMP14) and TIMPs (TIMP1-3) and the expression of miR-29 family members in ruptured supraspinatus tendons were compared with non-injured tendons of individuals without this lesion. Additionally, the gene expression and methylation status at the edge of the ruptured tendon were compared with macroscopically non-injured rotator cuff tendon samples from the anterior and posterior regions of patients with tendon tears. Moreover, the possible associations between the molecular alterations and the clinical and histologic characteristics were investigated. Dysregulated expression and DNA methylation of MMP and TIMP genes were found across the rotator cuff tendon samples of patients with supraspinatus tears. These alterations were influenced at least in part by age at surgery, sex, smoking habit, tear size, and duration of symptoms. Alterations in the studied MMP and TIMP genes may contribute to the presence of microcysts, fissures, necrosis, and neovascularization in tendons and may thus be involved in the tendon healing process. In conclusion, MMPs and their inhibitors are regulated by epigenetic modifications and may play a role in rotator cuff tears.

CYP genes in osteosarcoma: Their role in tumorigenesis, pulmonary metastatic microenvironment and treatment response.

Osteosarcoma (OS) is the most common malignant bone tumor in children and adolescents. The present study investigated the expression of Cytochrome P-450 (CYP) genes: CYP1A2, CYP3A4 and CYP3A5 by qRT-PCR in 135 specimens obtained from OS patients, including biopsy (pre-chemotherapy), tumor resected in surgery (post-chemotherapy), adjacent bone to tumor (nonmalignant tissue), pulmonary metastasis and adjacent lung to metastasis (nonmalignant tissue). Normal bone and normal lung tissues were used as control. We also investigated in five OS cell lines the modulation of CYPs expression by cisplatin, doxorubicin and methotrexate. As result, the adjacent lung specimens presented CYP1A2 overexpression compared to the normal lung (p=0.0256). Biopsy specimens presented lower CYP3A4 expression than normal bone (p=0.0314). The overexpression of both CYP1A2 and CYP3A4 in post-chemotherapy specimens were correlated with better event free-survival (p=0.0244) and good response (p=0.0484), respectively. Furthermore, in vitro assays revealed that CYP1A2 was upregulated by doxorubicin (p=0.0034); CYP3A4 was upregulated by cisplatin, doxorubicin and methotrexate (p=0.0004, p=0.0024, p<0.0001, respectively); and CYP3A5 was downregulated by doxorubicin (p=0.0285) and upregulated in time-dependent manner by methotrexate (p=0.0239). In conclusion, our findings suggest that CYP genes play an important role in OS tumorigenesis, at primary and metastatic sites, as well in treatment response.

MAPK pathways regulation by DUSP1 in the development of osteosarcoma: Potential markers and therapeutic targets.

Osteosarcoma (OS) is the most frequent primary bone tumor that affect children and adolescents. This tumor is highly aggressive with high risk of metastasis and the implementation of new drugs has not been successful. The search for biomarkers or new therapeutic targets is urgently needed and can help in advances of OS treatment. MAPKs are major signaling transduction molecules that play an important role in regulating a variety of cellular responses. DUSP1 is a phosphatase that dephosphorylates the MAPKs. Both MAPKs and DUSPs have been implicated as major modulators of critical signaling pathways that are dysregulated in various diseases. In a previous study, we found an increase in MAPK7 gene expression contributed for worst overall survival and treatment response. We analyzed gene expression of MAPK pathways that participate in MAPK7 regulation, and DUSP1 gene using paired 28 pre/post-chemotherapy and 12 metastasis OS samples. To understand the DUSP1 role in the pathogenesis of OS, we assessed the function of DUSP1 in four OS cell lines through a series of cellular assays combined with gene silencing technique. Our findings showed increased MAP2K6, MAP4K3, and DUSP1 gene expression in post-chemotherapy OS samples presenting poor prognosis. We also found that the suppression of DUSP1 gene expression resulted in decreased proliferation, migration, and invasion in OS cells. These results suggest that members of MAPK family may be possible prognostic markers in OS and DUSP1 has a relevant role in the OS pathogenesis and can be an attractive therapeutic target in new strategies of OS treatment.

Low-level laser therapy on bone repair of rat tibiae exposed to ionizing radiation.

OBJECTIVE: The purpose of this study was to evaluate the effects of low-level laser therapy (LLLT) on the repair of rat tibiae exposed to ionizing radiation (IR). BACKGROUND DATA: IR causes structural changes that delay bone tissue repair. Properly dosed, LLLT improves the bone repair process. METHODS: Seventy-two healthy Wistar rats were distributed into the following groups: Group I, sham control; Group II, LLLT; Group III, IR; and Group IV, IR and LLLT. Groups III and IV received a single dose (30 Gy) of gamma radiation and underwent surgery 28 days later. A noncritical sized bone defect (diameter 2.5 mm) was surgically created in all groups. Groups II and IV received three applications of postsurgical LLLT (GaAlAs, 808 nm, 100 mW, 0.028 cm(2), 3.57 W/cm(2), 20 sec, 2 J,≅71.4 J/cm(2)) on alternate days. Histomorphometry was assessed following digital image analysis. RESULTS: The samples were evaluated on days 7, 14, and 21 after surgery; the IR protocol resulted in a significant reduction (p<0.018) in bone formation in Group III compared with Group I. Significant increases (p<0.006) in newly formed bone were noted in Group IV compared with Group III. No significant differences were observed between Group I and Group IV. CONCLUSIONS: LLLT increased the newly formed bone area during the initial phase of the tibiae repair process in rats exposed to IR.

Investigation of IGF2, Hedgehog and fusion gene expression profiles in pediatric sarcomas.

UNLABELLED: The childhood sarcomas are malignant tumors with high mortality rates. They are divided into two genetic categories: a category without distinct pattern karyotypic changes and the other category showing unique translocations that originate gene rearrangements. This category includes rhabdomyosarcoma (RMS), Ewing's sarcoma (ES) and synovial sarcoma (SS). Diverse studies have related development genes, such as; IGF2, IHH, PTCH1 and GLI1 and sarcomatogenesis. OBJECTIVE: To characterize the RMS, ES and SS rearrangements, we quantify the expression of IGF2 IHH, PTCH1 and GLI1 genes and correlate molecular data with clinical parameters of patients. DESIGN: We analyzed 29 RMS, 10 SS and 60 ES tumor samples by RT-PCR (polymerase chain reaction-reverse transcription) and qPCR (quantitative PCR). RESULTS: Among the samples of ARMS, 50% had rearrangements of PAX3/7-FOXO1, 60% of ES samples were EWS-FLI1 positive and 90% of SS samples were positive for SS18-SSX1/2. In relation to the control reference samples (QPCR Human Reference Total RNA-Stratagene, Human Skeletal Muscle Total RNA-Ambion, Universal RNA Human Normal Tissues-Ambion), RMS samples showed a high IGF2 gene expression (p<0.0001). Moreover, ES samples showed a low IGF2 gene expression (p<0.0001) and high IHH (p<0.0001), PTCH1 (p=0.0173) and GLI1 (p=0.0113) gene expressions. CONCLUSIONS: The molecular characterization of IGF and Hedgehog pathway in these pediatric sarcomas may collaborate to enable a better understanding of the biological behavior of these neoplasms.

Analysis of KIAA1549-BRAF fusion gene expression and IDH1/IDH2 mutations in low grade pediatric astrocytomas.

Low-grade astrocytomas comprise about 30 % of the central nervous system tumors in children. Several investigations have searched a correlation between the BRAF gene fusions alterations and mutations at IDH1 and IDH2 genes in low grade pediatric astrocytomas. This study identified the expression of KIAA1549-BRAF fusion gene and BRAF V600E mutation, mutations at exon 4 of the IDH1 and IDH2 genes in samples of pilocytic astrocytomas (PA) and grade-II astrocytomas (A-II) pediatric patients. The correlation between these alterations and the clinical profile of the patients was also evaluated. Eighty-two samples of low-grade astrocytomas (65 PA and 17 A-II) were analyzed by PCR and sequencing for each of the targets identified. We identified the KIAA1549-BRAF fusion transcript in 45 % of the samples. BRAF V600E and BRAFins598T mutations were detected in 7 and 1 % of the samples, respectively. Mutations in the R132/R172 residues of the IDH1/IDH2 genes were detected in only two samples, and the G105G polymorphism (rs11554137:C>T) was identified in ten patients. Additionally, we observed two mutations out of the usual hotspots at IDH1 and IDH2 genes. We observed a smaller frequency of mutations in IDHs genes than previously described, but since the prior studies were composed of adult or mixed (adults and children) samples, we believe that our results represent a relevant contribution to the growing knowledge in low grade childhood astrocytomas.