6141 results for "canc*"

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• Tumor suppressor miR-133a modulates the prostate cancer epigenome by repressing BAZ2A

  Our study revealed a new subgroup of prostate tumors defined by the expression of a novel prognostic marker, BAZ2A, and the first time to show the establishment of CIMP via an microRNA-epigenetic interaction in prostate tumors.

  Study EGAS00001000568

• Novel Epigenetic Markers for Toxicity after Intraoperative and Conventional Radiotherapy for Breast Cancer

  Ionizing radiation is a common treatment option for cancer but its use is limited by the unpredictable and highly heterogeneous onset of late side effects, especially radiation-induced fibrosis. Clinically applicable biomarkers and effective treatments for radiation fibrosis are currently unavailable. In order to identify novel markers we ran a genome-wide DNA methylation screen in primary dermal fibroblasts obtained from breast cancer patients before intraoperative radiotherapy. Cells from patients developing fibrosis within a three-year follow up were compared to those without fibrosis (12 individuals per group). Illumina Infinium HumanMethylation450 BeadChip Technology was used.

  Study EGAS00001001279

• ABIS_1_MeDIP-seq

  We investigated changes in whole genome DNA-methylation in a group of 48 healthy five-year-old children differentiated by their hair cortisol levels. By combining this novel biomarker for chronic stress with methylated DNA immunoprecipitation sequencing (MeDIP-seq), we found that high cortisol were associated with a genome-wide decrease in DNA-methylation targeted to specific zinc finger transcription factor binding sites, repetitive elements and genes important for neurodevelopment and calcium transport. Large scale hypomethylation of repetitive regions, as well as a deficient calcium transport, have been reported in many stress related diseases, as well as in many cancers and biological aging. Thus our findings may aid in our understanding of how susceptibility to these diseases develops.

  Study EGAS00001001099

• RB Loss in Resistant EGFR Mutant Lung Adenocarcinomas that Transform to Small Cell Lung Cancer

  Tyrosine kinase inhibitors (TKIs) are effective treatments for non-small cell lung cancers (NSCLCs) with epidermal growth factor receptor (EGFR) mutations. However, they do not lead to cures, and, on average, relapse occurs typically occurs afterafter an average of one year of continuous treatment. In a subset of patients, aA fundamental histological transformation from NSCLC to small cell lung cancer (SCLC) is observed in a subset of the resistant cancers, but the molecular changes associated with this transformation remain unknown. Analysis of a cohort of tumor samples and cell lines derived from resistant EGFR mutant patients with SCLC transformation revealed that RB is lost in 100% of these SCLC transformed cases, but rarely in those that remain NSCLC. Global changes in gene expression, including increased neuroendocrine marker expression and absence of EGFR expression, are observed in resistant EGFR mutant cancers that transformed to SCLC. Consistent Further, with their similarities to classical SCLC at the genetic and gene expression levelincreased neuroendocrine marker and decreased EGFR expression as well as greater sensitivity to BCL2 family inhibition are observed in resistant SCLC transformed cancers compared to resistant NSCLCs. , cell lines derived from resistant EGFR mutant SCLC biopsies are substantially more sensitive to Bcl-2 family inhibition with ABT-263 compared to those derived from resistant EGFR mutant NSCLCs. Together, these findings suggest that despite developing initially as EGFR mutant adenocarcinomas, this subset of resistant cancers ultimately adopt many of the molecular and phenotypic characteristics of classical SCLC.

  Study EGAS00001001102

• Combined hereditary and somatic mutations of replication error repair genes result in rapid onset of ultra-hypermutated cancers

  DNA replication-associated mutations are repaired by two components: polymerase proofreading and mismatch repair. The mutational consequences of disruption to both repair components in humans are not well studied. We sequenced cancer genomes from children with inherited biallelic mismatch repair deficiency (bMMRD). High-grade bMMRD brain tumors exhibited massive numbers of substitution mutations (>250/Mb) – higher than all childhood and most cancers (>7000 analyzed). All ultra-hypermutated bMMRD cancers acquired early somatic driver mutations in DNA polymerases epsilon or delta. The ensuing mutation signatures and numbers are unique and diagnostic of childhood germline bMMRD (p<10e-13). Sequential tumor biopsy analysis revealed that bMMRD/polymerase mutant cancers rapidly amass an excess of simultaneous mutations (~600 mutations/cell division), reaching but not exceeding ~20,000 exonic mutations in <6 months. Thus implying a threshold compatible with cancer cell survival. We suggest a new mechanism of cancer progression in which mutations develop in a rapid burst after ablation of replication repair.

  Study EGAS00001001112

• Reproducibility of variant calls in replicate next generation sequencing experiments

  In this study, we examined the reproducibility of nucleotide variant calls in replicate sequencing experiments of the same genomic DNA. We performed targeted sequencing of all known human protein kinase genes (kinome) (~3.3 Mb) using the SOLiD v4 platform. Seventeen breast cancer samples were sequenced in duplicate (n=14) or triplicate (n=3) to assess concordance of all calls and single nucleotide variant (SNV) calls.

  Study EGAS00001000826

• Whole exome sequencing reveals the mutational spectrum of testicular germ cell tumours

  Testicular germ cell tumours (TGCTs) are the most common cancer in young men. Here we perform whole exome sequencing of 42 TGCTs to comprehensively study the mutational profile of TGCT. The mutation rate is uniformly low in all of the tumours (mean 0.5 mutations per megabase [Mb]) as compared to the common cancers, consistent with the embryological origin of TGCT. In addition to expected copy number gain of chromosome 12p and mutation of KIT we identify recurrent mutations in the tumour suppressor gene CDC27 (11.9%). Copy number analysis reveals recurring amplification of the spermatocyte development gene FSIP2 (15.3%) and a 0.4Mb region at Xq28 (15.3%). Two treatment-refractory patients are shown to harbour XRCC2 mutations, a gene strongly implicated in defining cisplatin resistance. Our findings provide further insights into genes involved in the development and progression of TGCT.

  Study EGAS00001001084

• Capture Hi-C identifies the chromatin interactome of colorectal cancer risk loci

  Multiple regulatory elements distant to their targets on the linear genome can influence the expression of a single gene through chromatin looping. Chromosome conformation capture implemented in Hi-C allows for genome-wide agnostic characterization of chromatin contacts. However, detection of functional enhancer-promoter interactions is precluded by its effective resolution that is determined by both restriction fragmentation and sensitivity of the experiment. Here we have developed a capture Hi-C (cHi-C) approach to allow an agnostic characterisation of these physical interactions on a genome-wide scale. Single nucleotide polymorphisms associated with complex diseases often reside within regulatory elements and exert effects through long-range regulation of gene expression. Applying this cHi-C approach to 14 colorectal cancer risk loci has allowed us to identify key long-range chromatin interactions in cis and trans involving these loci.

  Study EGAS00001001085

• Therapeutic Resistance to PI3K-alpha Inhibitors

  We have studied the tumor genomic evolution in a patient with metastatic breast cancer bearing an activating PIK3CA mutation. The patient was treated with the PI3Kα inhibitor BYL719 and achieved a lasting clinical response on BYL719, but eventually progressed to treatment and died shortly thereafter. A rapid autopsy was performed and a total of 14 metastatic lesions were collected for further analysis. In order to identify possible genetic determinants of acquired resistance to PI3Kα inhibition, we took a three-step approach. First, we examined both the primary tumor (before BYL719 treatment) and the new lung metastasis by whole genome sequencing (DNA from the spleen was used as a normal control). Then, we analyzed the primary tumor, lung metastasis, and the peri-aortic lesion that remained stable (responding) at the time of progression to BYL719 therapy by whole exome sequencing. Finally, to confirm and expand our findings, we sequenced the primary tumor and all the metastatic lesions to >500-fold coverage using a custom targeted deep-sequencing assay, MSK-IMPACT. Using this 3-step approach, we have demonstrated that patient’s lesion underwent parallel genetic evolution at multiple metastatic sites with different PTEN genomic alterations leading to a convergent PTEN- null phenotype resistant to PI3Kα inhibition. In order to expand our observations, we analyzed paired samples (pre-treatment and at progression) from six additional patients enrolled in the BYL719 trial. Acquired bi-allelic loss of PTEN was found in one additional patient treated with BYL719 whereas in two patients PIK3CA mutations present in the primary tumor were no longer detected at the time of progression. To functionally characterize our findings, inducible PTEN knockdown in sensitive cells resulted in resistance to BYL719, while simultaneous PI3K-p110β blockade reverted this resistance phenotype, both in cell lines and in PTEN-null xenografts derived from our patient. We conclude that parallel genetic evolution of separate sites with different PTEN genomic alterations leads to a convergent PTEN-null phenotype resistant to PI3Kα inhibition.

  Study EGAS00001000991

• Whole exome sequencing of papillary thyroid carcinoma in the Chinese population

  Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer. Here we submitted the sequencing results for PTC using 91 tumor-normal pairs through exome sequencing in the Chinese Han population.

  Study EGAS00001001268