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    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.
    Full-text · Article · Jul 2013 · Human pathology
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    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.
    Full-text · Article · Oct 2012 · Growth hormone & IGF research: official journal of the Growth Hormone Research Society and the International IGF Research Society
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    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.
    Full-text · Article · Jul 2012 · Cytotechnology
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