9296 results for "cancer rna-seq"

in 108.00 milliseconds.

• Evolutionary dynamics of residual disease in human glioblastoma

  Glioblastoma is the most common and aggressive adult brain malignancy against which conventional surgery and chemoradiation provide limited benefit. Even when a good treatment response is obtained, recurrence inevitably occurs either locally (c.80%) or distally (c.20%), driven by cancer clones that are often genomically distinct from those in the primary tumour. Glioblastoma cells display a characteristic infiltrative phenotype, invading the surrounding tissue and often spreading across the whole brain. We hypothesised that cancer cells responsible for relapse reside in two compartments of residual disease that are left behind after treatment: the infiltrated normal brain parenchyma, and the sub-ventricular zone (SVZ). In this model, residual disease subclones diverge early during glioblastoma evolution, may remain dormant in the normal parenchyma and are responsible for recurrence. To test our hypothesis, we performed whole-exome sequencing of 69 multi- region samples collected using fluorescence-guided resection from 11 patients, including the infiltrating tumour margin (M) and the SVZ for each patient, as well as matched blood. We used a phylogenomic approach to dissect the spatio-temporal evolution of each tumour and unveil the relation between residual disease and the main tumour mass. We also analysed two patients with paired primary-recurrence samples with matched residual disease. Our results suggest that the infiltrative phenotype is an early evolutionary trait of glioblastoma, giving rise to the tumour mass detected at surgery. After treatment, the same infiltrative clone may seed the growth of a recurrent tumour, thus representing the ‘missing link’ between the primary tumour and recurrent disease. These results are consistent with recognised clinical phenotypic behaviour and suggest that more specific therapeutic targeting of cells in the infiltrated brain parenchyma may improve patient’s outcome.

  Study EGAS00001003043

• 1 Intratumoral genetic heterogeneity and clonal evolution following neoadjuvant chemoradiotherapy (nCRT) in locally advanced rectal tumors.

  Purpose: Neoadjuvant chemoradiotherapy (nCRT) is the standard treatment forpatients with locally advanced rectal cancer. However, little is known about the effect of nCRT in the mutational landscape and intratumoral genetic heterogeneity (ITGH) of rectal tumors. Moreover, response to nCRT vary substantially among patients and the genetic determinants of treatment response are not fully understood. Here, we sought to determine the impact of nCRT in the mutational landscape and ITGH of rectal tumors and to identify putative drivers of therapeutic resistance. Patients and Methods: We analyzed whole-exome sequencing (WES) and clinical data from 79 primary non-treated rectal cancers obtained from The Cancer Genome Atlas (TCGA). We also compared the mutational landscape of a matched set of peripheral blood cells, irradiated tumor-adjacent colonic mucosa and pre and post-treatment tumor samples to determine the iatrogenic effects of nCRT and its impact in tissue genetic heterogeneity. Finally, we performed WES of 7 matched pre and post-treatment tumor samples to examine how nCRT affects the clonal architecture of rectal tumors. Results: We show that rectal tumors exhibit remarkable ITGH, which increases with disease progression. We also show that nCRT, per se, does not introduce novel somatic mutations, nor alters the clonal architecture of the irradiated colonic mucosa. Instead, we show that it acts as a potent selective pressure, favoring the expansion of tumor cell subpopulations more prone to resist therapy and increasing ITGH in the residual tumor. Conclusion: Our results reveal the highly heterogeneous and dynamic clonal architecture of rectal tumors undergoing nCRT. Our results also uncover putative genetic determinants of response to nCRT and a possible role for ITGH in predicting treatment outcome.

  Study EGAS00001003250

• National Cancer Institute Clinical and Laboratory Analysis of Familial Cancer

  The purpose of this study is to continue the analysis begun on 09C0079 which was focused on identification of the genetic mutation associated with a new gastric polyposis syndrome, Gastric Adenocarcinoma and Proximal Polyposis of the Stomach (GAPPS). GAPPS, first described in 2012, is an autosomal dominant gastric polyposis syndrome that confers a substantial risk for gastric adenocarcinoma. The GAPPS phenotype consists of a carpeting of greater than 100 fundic gland polyps (FGPs) in the oxyntic mucosa of the gastric body and fundus, with antral sparing with some FGPs displaying high-grade dysplasia. This is in contrast to sporadic FGPs that are benign, most often are not associated with high-grade dysplasia though low-grade dysplasia has been reported, and are fewer in number. Gastric FGPs have been found to be associated with Familial Adenomatous Polyposis (FAP) and attenuated FAP, which is an autosomal dominant condition associated with germ line mutations in APC which confers a phenotype consisting of multiple (>100) adenomatous polyps in the colon and rectum developing after the first decade of life. FGPs are reported to occur in 12-84% of patients with FAP, whereas sporadic FGPs are identified in ~5% of patients undergoing upper gastrointestinal endoscopy. Gastric adenocarcinoma arising from FGPs in individuals with FAP have been reported. Other manifestations of FAP and AFAP include polyps in the upper gastrointestinal tract, congenital hypertrophy of retinal pigment epithelium, osteomas and epidermoid cysts, supernumerary teeth, desmoid formation, and other malignancies such as thyroid, small bowel cancer, hepatoblastoma, and medulloblastoma. Thus far there are no reports in GAPPS of polyposis arising in the esophagus, gastric antrum, pylorus, small intestine, or colon.

  Study phs001935

• WES dataset of 20 pre-post paired neoadjuvant chemotherapy treated breast cancer samples

  This dataset contains whole exome sequencing data (WES) of 20 paired pre- and post neoadjuvant chemotherapy breast cancer samples. From every patient a pre-treatment biopsy (B) and a post-treatment surgery (S) specimen has been sequenced. From most patients a paired normal blood sample (N) has been sequenced as a reference control.

  Dataset EGAD00001008442

• Southern African Prostate Cancer Study (SAPCS) Ethnic Disparity

  The cohort (n=130) consists of prostate cancer patients from South Africa (n=123) and Brazil (n=7). For each patient, a pair of blood and tumour samples were collected. The sequencing data was mapped to hg38 reference. Blood BAMs are named with “-B” as suffix and tumour BAMs are named with “-T” as suffix.

  Dataset EGAD00001009067

• WGS_of_healhy_mesothelial_cells_and_primary_mesothelima_cell_lines

  Mesothelioma is a rare and aggressive cancer associated with previous exposure to asbestos. Currently there are no effective treatments for mesothelioma and majority of patients will die within a year after diagnosis. Although a large number of preclinical and clinical trials assessed the efficacy of various therapuetic modes, none of the tested molecules entered the clinic. Thus, to better understand what drives mesothelioma carcinogenesis and to identify novel targets for therapy, here we aim at performing WGS of heathy mesothelial cells and a panel of mesothelioma cells lines. Primary mesothelial cell lines were established in prof. Marciniak lab from human pleural specimens, while primary mesothelioma cell lines were obtained from MesobanK. Both models constitute low passage cell lines and therefore should closely represent genetics of the original tissue.

  Study EGAS00001005559

• Targeting PTPRK-RSPO3 colon tumours promotesdifferentiation and loss of stem-cell function

  Colorectal cancer remains a major unmet medical need, promptinglarge-scale genomics efforts in the field to identify moleculardrivers for which targeted therapies might be developed. Wepreviously reported the identification of recurrent translocationsin R-spondin proteins present in a subset of colorectal tumours.Here we show that targeting RSPO3 in PTPRK-RSPO3-fusion positivehuman tumour xenografts inhibits tumour growth andpromotes differentiation. Notably, genes expressed in the stem-cellcompartment of the intestine were among those most sensitive toanti-RSPO3 treatment. This observation, combined with functionalassays, suggests that a stem-cell compartment drives PTPRK-RSPO3colorectal tumour growth and indicates that the therapeutictargeting of stem-cell properties within tumours may be a clinicallyrelevant approach for the treatment of colorectal tumors.

  Study EGAS00001001462

• A PROSTATE TUMORGRAFT PANEL TO ACCELERATE PRECISION MEDICINE

  The management of advanced prostate cancer (PCa) has strongly evolved in the last decade with the introduction of the next generation of androgen receptor pathway inhibitors which have considerably improved patient outcomes. Most recently, the investigation of genomic landscape has provided targetable molecular alterations such as homologous gene DNA repair defects correlated with response to PARP inhibitors. Despite these significant advances, while localized PCa is generally associated with favorable outcome, metastatic PCa is currently considered incurable. For further investigations in precision treatment, the development of preclinical models representing the complex prostate tumor heterogeneity are mandatory. Accordingly, we aimed to establish a resource of patient-derived xenograft (PDX) models that exemplify each phase of this multistage disease for accurate and rapid evaluation of candidate therapies.

  Study EGAS00001007033

• Genomic characterization of esophageal squamous cell carcinoma reveals critical genes underlying tumorigenesis and poor prognosis

  The genetic mechanisms underlying the poor prognosis of esophageal squamous cell carcinoma (ESCC) are not well understood. In this study, we comprehensively characterized somatic mutations, copy number alterations (SCNAs)/structural variants (SVs) found in ESCC from sequencing 10 whole-genome and 57 whole-exome matched tumor-normal pairs. We identified multiple somatic mutations seen previously in known cancer pathways and identified candidate genes for ESCC including VANGL1 and MIR4707. A survival analysis based on the expression profiles of 321 ESCC individuals indicated that the somatically altered genes we found were significantly associated with ESCC poorer survival. Subsequently, we performed functional studies to validate the roles of the altered genes in tumor proliferation and metastasis.

  Study EGAS00001001723

• Genome-wide analysis of HPV integration in human cancers reveals recurrent, focal genomic instability

  Genomic instability is a hallmark of human cancers, including the 5% caused by human papillomavirus (HPV). Here we report a striking association between HPV integration and adjacent host genomic structural variation in human cancer cell lines and primary tumors. Whole genome sequencing revealed HPV integrants flanking and bridging extensive host genomic amplifications and rearrangements, including deletions, inversions and chromosomal translocations. We present a model of ³looping² by which HPV integrant-mediated DNA replication and recombination may result in viral-host DNA concatemers, frequently disrupting genes involved in oncogenesis and amplifying HPV oncogenes E6 and E7. Our high-resolution results shed new light on a catastrophic process, distinct from chromothripsis and other mutational processes, by which HPV directly promotes genomic instability.

  Study EGAS00001000599