Genome profiling by comparative genomic hybridization (CGH) in pediatric osteosarcoma
Ontology highlight
ABSTRACT: In some types of cancer, telomere length is maintained by the Alternative Lengthening of Telomeres (ALT) mechanism. We characterized a series of high-grade osteosarcomas from 22 non-metastatic and non-pre-treated pediatric patients. Using the presence of circular partially single-stranded extrachromosomal C-rich telomeric repeat sequences (C-Circles) as an ALT marker, we found that 16 of the 22 high-grade osteosarcomas were ALT-positive. In order to find copy number alterations associated with ALT mechanims, we used comparative genomic hybridization (CGH).
Project description:DNA microarrays were used to define the transcriptional profiles of tumor samples to compare 12 high-grade pediatric osteosarcoma tumor samples on their ALT and ATRX status.
Project description:We conducted a prospective monocenter clinical trial called PERMED01 to evaluate the number patients with locally advanced or metastatic cancer for whom identification of molecular alterations in tumor samples could lead to the delivery of a targeted therapy. Patients accessible to tumor biopsy were prospectively enrolled at the Paoli-Calmettes Institute in the PERMED01 study (ClinicalTrials.gov, NCT02342158). Genomic profiling of frozen tissue was established by whole-genome array comparative genomic hybridization (aCGH)
Project description:Papillary renal cell carcinomas (pRCC) are the second most common form of renal carcinoma, after clear cell Renal carcinoma (ccRCC). PRCC account for 10 to 15% of RCC and gather a heterogeneous population with no specific systemic treatment. Pathological classification by Elbe divides pRCC population in two morphologically different subtypes. Type 1 consists of predominantly basophilic cells, whereas type 2 contains mostly eosinophilic cells. Type 1 architecture corresponds with a single line of cells along the papillary axis, whereas type 2 generally exhibits several cell strata on the axis. Furthermore, type 2 cells demonstrate more aggressive characteristics, such as the presence of nucleoli and increased nuclear size. The papillary cores often contain edema fluid, foamy macrophages, and psammoma bodies. Further clinical reports identified that type I tumors are more likely to present as numerous, bilateral , indolent, low grade pRCC, whereas type II are associated with higher grade and poor prognosis related to metastatic evolution. The goal of this study wad to characterize each sample in order to get an idea of the genomic profile in pRCC type 2 (pRCCII).
Project description:We performed a differential analysis of copy-number-alterations (CNAs) and mutations profiles by using pan-genomic array-CGH and next-generation-sequencing of 365 ‘cancer-associated’ genes, in a series of 14 pairs of matched primary breast cancer (PBC)/brain metastasis (BM) and assessed if the observed genomic alterations may be used as a druggable agent in a clinical trial.
Project description:Background<br>Primitive brain tumors are the first cause of cancer-related death in children. Tumor cells with stem-like properties (TSCs), thought to account for tumorigenesis and therapeutic resistance, have been isolated from high-grade gliomas in adults. Whether TSCs are a common component of pediatric brain tumors and are of clinical relevance remains to be determined. <br>Methodology/Principal findings<br>Tumor cells with self-renewal properties were isolated with cell biology techniques from a majority of 55 pediatric brain tumors samples, regardless of their histopathologies and grades of malignancy (57% of embryonal tumors, 57% of low-grade gliomas and neuro-glial tumors, 70% of ependymomas, 91% of high-grade gliomas). The vast majority (10/12) of high-grade glioma-derived oncospheres sustained long-term self-renewal numbers akin to neural stem cells (>7 self-renewals), whereas cells with limited renewing abilities akin to neural progenitors dominated in all other tumor types. Regardless of tumor entities, the young age group was associated with self-renewal properties akin to neural stem cells (P=0.05, chi-square test). TSCs shared a complex molecular profile combining embryonic stem cell markers with elements controlling neural stem cell properties and epithelio-mesenchymal transitions. They were radio- and chemoresistant and formed aggressive tumors after intracerebral grafting. Survival analysis of the cohort showed an association between isolation of TSCs with long-term self-renewal abilities and a patients higher mortality rate (P = 0.022, log-rank test). Patients bearing cells with limited self-renewal properties constituted an intermediate group of survival but which did not reach statistical significance. <br>Conclusions/Significance<br>In brain tumors affecting adult patients, TSC have been isolated only from high-grade gliomas. In contrast, our data show that tumor cells with stem cell-like or progenitor-like properties can be isolated from a wide range of histological sub-types and grades of pediatric brain tumors. They suggest that cellular mechanisms fueling tumor development differ between adult and pediatric brain tumors.<br>
Project description:Gliosarcoma, a rare glioblastoma variant, is composed of a glial and a mesenchymal component. Though the mesenchymal portion most commonly resembles a fibrosarcoma, other differentiation patterns have been observed. We present the first genomic characterisation (karyotyping followed by FISH and array-CGH analysis) of a gliosarcoma with osseous metaplasia. In addition to chromosomal changes often found in gliomas (+7,-10,-13, and -22), the tumour cells also harboured a hitherto unknown 3q21;21q21~22-translocation. As translocations are very rare in high-grade astrocytic tumours and have not formerly been seen in gliosarcomas, it is possible that the t(3;21) may be characteristic of gliosarcoma with osseous metaplasia. Tumour sample analysed with control DNA (supplied by Agilent)
Project description:Hormone therapy (HT) is an effective treatment for metastatic endometrial carcinoma (mEC), with limited toxicity and low cost. We focused on molecular analysis of mECs treated by HT and, for the first time to date, we compared genomic profiles of paired metastasis and primary ECs. The main objective was to identify predictive factors of response to HT as well as specific altered signalling pathways driving mEC biology. We evaluated gene alterations by array-based comparative genomic hybridization
Project description:Nectin-4 is a new therapeutic target in various carcinomas. We were interested in resistance to anti-nectin 4 ADC in breast cancer and the way to overcome it. Tumor DNA were extracted from sensitive and resistant pre-clinical models. Genomic profiles of samples were established by using array-CGH onto 4×180K CGH microarrays.
Project description:The Alternative Lengthening of Telomeres (ALT) facilitates telomere lengthening by a DNA strand invasion and copying mechanism. The nuclear receptor NR2F2 can bind to (TCAGGG)n variant repeats within telomeres and it has been proposed that this facilitates telomere interactions in ALT+ cells. However, the role NR2F2 in regulation the gene expression in ALT+ cell lines is unclear. Here, using Next Generation Sequencing (NGS), we characterised the changes in expression profile of three ALT+ cell lines (W-V, WI38VA13/2RA, U2OS) upon transient siRNA mediated downregulation of NR2F2 compared to cells treated with a control siRNA . Among 86 ALT-associated genes, only MND1 showed consistent down-regulation across the three NR2F2-depleted ALT+ cell lines. Altogether our data indicate that NR2F2 it does not play a direct role in the ALT mechanism.
Project description:Affymetrix gene expression data of 21 high-grade osteosarcomas located in the extremities.This gene expression profiling was performed in order to evaluate the expression of candidate prognostic and therapeutic targets in high-grade osteosarcoma.