[Show abstract][Hide abstract] ABSTRACT: Osteosarcoma is a malignant bone tumor with high metastatic potential. Metastasis at diagnosis is the most significant prognostic factor in predicting the clinical outcome of osteosarcoma. We compared the gene expression of metastases that were present at the time of initial diagnosis to those developed later in the course of the disease. We used quantitative real-time polymerase chain reaction to evaluate the gene expression of MDM2, CXCR4, RANKL, RB1, and OSTERIX in 98 samples of osteosarcoma taken from 47 patients (74 metastases and 24 primary tumors) and 30 nonmalignant lung tissues surrounding osteosarcoma metastases. In addition, we investigated the copy number changes of RB1 and MDM2 genes in 12 primary cultures of pulmonary metastases of osteosarcoma, using interphase fluorescence in situ hybridization. Metastases from metastatic patients at diagnosis were characterized by low expression of RB1 and RANKL (P = .0009 and P = .0109, respectively) and overexpression of CXCR4 and MDM2 (P = .0389 and P = .0325, respectively). The loss of RANKL and gain of CXCR4 could also be detected in the primary tumors of metastatic patients at diagnosis (P = .0121 and P = .0264, respectively). Thus, some early genetic events such as the loss of RANKL and the gain of CXCR4 expressions probably facilitate the metastatic progression concomitant with the primary tumor establishment, supporting the role of the CXCR4 receptor in directing osteosarcoma metastases to the lung. On the other hand, late events such as the loss of RB1 and gain of MDM2, crucial regulators of cell cycle, appear to be related to the final mechanisms contributing to the metastatic establishment of osteosarcoma.
[Show abstract][Hide abstract] ABSTRACT: The purpose of our study was to investigate the prevalence of the PAX3/7-FKHR fusion genes and quantify the IGF2 gene expression in rhabdomyosarcoma (RMS) samples. Soft tissue sarcomas account 5% of childhood cancers and 50% of them are RMS. Morphological evaluation of pediatric RMS has defined two histological subtypes, embryonal (ERMS) and alveolar (ARMS). Chromosomal analyses have demonstrated two translocations associated with ARMS, resulting in the PAX3/7-FKHR rearrangements. Reverse transcriptase-polymerase chain reaction (RT-PCR) is extremely useful in the diagnosis of ARMS positive for these rearrangements. Additionally, several studies have shown a significant involvement of IGF pathway in the pathogenesis of RMS. The presence of PAX3/7-FKHR gene fusions was studied in 25 RMS samples from patients attending the IOP-GRAACC/UNIFESP and three RMS cell lines by RT-PCR. IGF2 gene expression was quantified by qPCR and related with clinic pathological parameters. Of the 25 samples, nine (36%) were ARMS and 16 (64%) were ERMS. PAX3/7-FKHR gene fusions expression was detected in 56% of ARMS tumor samples. IGF2 overexpression was observed in 80% of samples and could indicate an important role of this pathway in RMS biology.
Growth hormone & IGF research: official journal of the Growth Hormone Research Society and the International IGF Research Society 10/2012;
[Show abstract][Hide abstract] ABSTRACT: Osteosarcoma (OS) is the most frequent malignant bone tumour in children and adolescents. In metastatic patients, the most common site of metastasis is the lung. There are relatively few cell lines of metastatic OS reported in the literature and the cytogenetic aspects of OS metastases are still controversial and inconclusive. Here we describe the establishment of a new OS cell line, M-OS, from a pulmonary metastasis of a typical osteoblastic OS of an 11-year-old boy with metastatic OS at diagnosis. M-OS cells have been maintained in culture for over 50 passages for more than 1 year. M-OS was characterized by immunohistochemistry, conventional cytogenetics and fluorescence in situ hybridization (FISH). In order to evaluate in vitro cell modification, the immunohistochemical analysis was performed in three different moments of the cell line: 10th, 30th and 50th passages. The conventional cytogenetic analysis revealed the ploidy of M-OS cell line as near-diploid, with most metaphases hyperdiploid and tetraploid. We found a copy number gain of MDM2 gene as the most frequent alteration in the FISH analysis. The immunohistochemical analysis confirmed that M-OS cell line maintained the osteogenic nature even after all passages for the cell line establishment in vitro.
[Show abstract][Hide abstract] ABSTRACT: Usual treatment regimens with vancomycin often fail to provide adequate serum levels in patients with severe infections.
Retrospective analysis of vancomycin trough serum measurements. The following parameters were calculated by Bayesian analysis: vancomycin clearance, distribution volume, and peak estimated concentrations. The area under the concentration curve (AUC) (total daily dose/24 h clearance of vancomycin) was used to determine the effectiveness of treatment through the ratio of AUC/minimum inhibitory concentration (MIC) above 400, using MIC=1 μg/mL, based on isolates of Staphylococci in cultures.
Sixty-one vancomycin trough measurements were analyzed in 31 patients. AUC/MIC>400 was obtained in 34 out of 61 dosages (55.7%), but the mean vancomycin dose required to achieve these levels was 81 mg/kg/day. In cases where the usual doses were administered (40-60 mg/kg/day), AUC/MIC>400 was obtained in nine out of 18 dosages (50%), in 13 patients. Trough serum concentrations above 15 mg/L presented a positive predictive value of 100% and a negative predictive value of 71% for AUC/MIC>400.
Higher than usual vancomycin doses may be required to treat staphylococcal infections in children with oncologic/hematologic diseases. Since the best known predictor of efficacy is the AUC/MIC ratio, serum trough concentrations must be analyzed in conjunction with MICs of prevalent Staphylococci and pharmacokinetic tools such as Bayesian analysis.
The Brazilian journal of infectious diseases: an official publication of the Brazilian Society of Infectious Diseases 07/2012; 16(4):361-5.
[Show abstract][Hide abstract] ABSTRACT: In Brazil, the majority of the population does not have private health insurance and the government provides universal health care. Our 'Unique Healthcare System' pays for 95% of the 1500 hematopoietic stem cell transplants (HSCT) performed in the country every year. Hospitals are reimbursed a flat rate, ranging from US$ 13,000 for autologous to US$ 40,500 for unrelated donor transplants, excluding expenses with donor search and acquisition of the graft. The actual cost of the procedure is not captured routinely. Because unrelated donor recipients may have many clinical complications, most HSCT centers offer few or no beds to perform such transplants. The Pediatric Oncology Institute - GRAACC - is a non-profit organization that provides comprehensive care at no cost to the families, including unrelated donor HSCT. We are evaluating retrospectively the unrelated donor transplant costs to have data to present to the health authorities, looking for an appropriate funding formula for HSCT.
[Show abstract][Hide abstract] ABSTRACT: Osteosarcoma is a class of cancer originating from the bone, affecting mainly children and young adults. Cytogenetic studies showed the presence of rearrangements and recurrent gains in specific chromosomal regions, indicating the possible involvement of genes located in these regions during the pathogenesis of osteosarcoma. These studies investigated expression of 10 genes located in the chromosomal region involved in abnormalities in osteosarcoma, 1p36, 17p, and chromosome 19. The purpose of this study was to investigate the expression profile of genes located in regions involved in chromosomal rearrangements in osteosarcoma. We used quantitative real-time polymerase chain reaction to investigate the expression of 10 genes located in 1p36.3 (MTHFR, ERRFI1, FGR, E2F2), 17p (MAPK7, MAP2K4), and chromosome 19 (BBC3, FOSB, JUND, and RRAS), in 70 samples taken from 30 patients (30 prechemotherapy, 30 postchemotherapy, and 10 metastases specimens) and 10 healthy bones as a control sample. The most interesting results showed a strong association between the expression levels of MAPK7 and MAP2K4 genes and clinical parameters of osteosarcoma. Overexpression of these genes was significantly associated to a poor response to treatment (P = .0001 and P = .0049, respectively), tumor progression, and worse overall survival (P = .0052 and P = .0085, respectively), suggesting that MAPK7 and MAP2K4 could play an important role in osteosarcoma tumorigenesis. Thus, these genes could be good markers in assessing response to treatment and development of osteosarcoma.
[Show abstract][Hide abstract] ABSTRACT: Aberrant expression of stem cell-related genes in tumors may confer more primitive and aggressive traits affecting clinical outcome. Here, we investigated expression and prognostic value of the neural stem cell marker CD133, as well as of the pluripotency genes LIN28 and OCT4 in 37 samples of pediatric medulloblastoma, the most common and challenging type of embryonal tumor. While most medulloblastoma samples expressed CD133 and LIN28, OCT4 expression was found to be more sporadic, with detectable levels occurring in 48% of tumors. Expression levels of OCT4, but not CD133 or LIN28, were significantly correlated with shorter survival (P ≤ 0.0001). Median survival time of patients with tumors hyperexpressing OCT4 and tumors displaying low/undetectable OCT4 expression were 6 and 153 months, respectively. More importantly, when patients were clinically stratified according to their risk of tumor recurrence, positive OCT4 expression in primary tumor specimens could discriminate patients classified as average risk but which further deceased within 5 years of diagnosis (median survival time of 28 months), a poor clinical outcome typical of high risk patients. Our findings reveal a previously unknown prognostic value for OCT4 expression status in medulloblastoma, which might be used as a further indicator of poor survival and aid postoperative treatment selection, with a particular potential benefit for clinically average risk patients.
[Show abstract][Hide abstract] ABSTRACT: Medulloblastoma is the most common malignant tumors of central nervous system in the childhood. The treatment is severe, harmful and, thus, has a dismal prognosis. As PRAME is present in various cancers, including meduloblastoma, and has limited expression in normal tissues, this antigen can be an ideal vaccine target for tumor immunotherapy. In order to find a potential molecular target, we investigated PRAME expression in medulloblastoma fragments and we compare the results with the clinical features of each patient. Analysis of gene expression was performed by real-time quantitative PCR from 37 tumor samples. The Mann-Whitney test was used to analysis the relationship between gene expression and clinical characteristics. Kaplan-Meier curves were used to evaluate survival. PRAME was overexpressed in 84% samples. But no statistical association was found between clinical features and PRAME overexpression. Despite that PRAME gene could be a strong candidate for immunotherapy since it is highly expressed in medulloblastomas.
Arquivos de neuro-psiquiatria 02/2011; 69(1):9-12.
[Show abstract][Hide abstract] ABSTRACT: Medulloblastomas are the most common malignant tumors of the central nervous system in childhood. The incidence is about 19-20% between children younger than 16 years old with peak incidence between 4 and 7 years. Despite its sensibility to no specific therapeutic means like chemotherapy and radiotherapy, the treatment is very aggressive and frequently results in regression, growth deficit, and endocrine dysfunction. From this point of view, new treatment approaches are needed such as molecular targeted therapies. Studies in glioblastoma demonstrated that ASPM gene was overexpressed when compared to normal brain and ASPM inhibition by siRNA-mediated inhibits tumor cell proliferation and neural stem cell proliferation, supporting ASPM gene as a potential molecular target in glioblastoma. The aim of this work was to evaluate ASPM expression in medulloblastoma fragment samples, and to compare the results with the patient clinical features.
Analysis of gene expression was performed by quantitative PCR real time using SYBR Green system in tumor samples from 37 children. The t test was used to analyze the gene expression, and Mann-Whitney test was performed to analyze the relationship between gene expressions and clinical characteristics. Kaplan-Meier test evaluated curve survival.
All samples overexpressed ASPM gene more than 40-fold. However, we did not find any association between the overexpressed samples and the clinical parameters.
ASPM overexpression may modify the ability of stem cells to differentiate during the development of the central nervous system, contributing to the development of medulloblastoma, a tumor of embryonic origin from cerebellar progenitor cells.
[Show abstract][Hide abstract] ABSTRACT: Osteosarcoma is the most common malignant bone tumor in children and adolescents. Multidrug resistance and poor clinical outcome are the problems that still affect osteosarcoma patients. The glutathione S-transferase supergene family includes several genes that encode enzymes involved in the detoxification of many xenobiotic agents, including carcinogens and anticancer drugs. The polymorphisms in these genes have already been associated both with cancer susceptibility and anticancer drugs resistance.
This study aims to investigate the genotype frequencies of GSTM1, GSTT1 and GSTM3 genes in 80 osteosarcoma patients and 160 normal control participants, and also the influence of these polymorphisms in the clinical outcome of osteosarcoma patients.
GSTM1 and GSTT1 deletion polymorphisms were examined through a multiplex-PCR and the GSTM3 polymorphism of three base pair-deletion at intron 6 using PCR-restriction fragments length polymorphism method.
We found that GSTM1 null genotype is correlated to poor clinical outcome characterized by the increased lung relapse occurrence [odds ratio (OR)=2.71, P=0.036], while the presence of at least one GSTM1 allele is associated with a good response to treatment and better survival (OR=4.28, P=0.020 and hazards ratio=4.09, P=0.0078, respectively). The GSTT1 null genotype was correlated with a better overall survival (hazards ratio=7.15, P=0.0247), whereas GSTM3*B allele was associated with metastasis at diagnosis (OR=2.83, P=0.028).
The findings of this study suggest that GST polymorphisms may have a role in treatment response and osteosarcoma progression.
Pharmacogenetics and Genomics 08/2010; 20(8):507-15.
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