Glioblastoma multiforme (GBM) is the most common and lethal type of brain cancer. To identify the genetic alterations in GBMs, we sequenced 20,661 protein coding genes, determined the presence of amplifications and deletions using high-density oligonucleotide arrays, and performed gene expression analyses using next-generation sequencing technologies in 22 human tumor samples. This comprehensive analysis led to the discovery of a variety of genes that were not known to be altered in GBMs. Most notably, we found recurrent mutations in the active site of isocitrate dehydrogenase 1 (IDH1) in 12% of GBM patients. Mutations in IDH1 occurred in a large fraction of young patients and in most patients with secondary GBMs and were associated with an increase in overall survival. These studies demonstrate the value of unbiased genomic analyses in the characterization of human brain cancer and identify a potentially useful genetic alteration for the classification and targeted therapy of GBMs. †To whom correspondence should be addressed. E-mail: bertvog@gmail.com (B.V.); velculescu@jhmi.edu (V.E.V.); kinzlke@jhmi.edu (K.W.K.). * These authors contributed equally to this work. NIH Public Access Author ManuscriptScience. Author manuscript; available in PMC 2010 February 11. Published in final edited form as:Science. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptMalignant gliomas are the most frequent and lethal cancers originating in the central nervous system. The most biologically aggressive subtype is glioblastoma multiforme (GBM) [World Health Organization (WHO) grade IV astrocytoma], a tumor associated with a dismal prognosis (1). The current standard of care for GBM patients-surgical resection followed by adjuvant radiation therapy and chemotherapy with the oral alkylating agent temozolomideproduces a median survival of only 15 months (2). Historically, GBMs have been categorized into two groups ("primary" and "secondary") on the basis of clinical presentation (3). Secondary GBMs are defined as cancers that have clinical, radiologic, or histopathologic evidence of malignant progression from a preexisting lower-grade tumor, whereas primary GBMs have no such history and present at diagnosis as advanced cancers (4). Clinical differences have been re ported between the two groups, with secondary GBMs occurring less frequently (~5% of GBMs) and predominantly in younger patients (median age ~45 years versus ~60 years for primary GBM) (5,6). The histopathologic findings of primary and secondary GBMs are indistinguishable, and the prognosis does not appear to be different after adjustment for age (5,6).Substantial research effort has focused on the identification of genetic alterations in GBMs that might help define subclasses of GBM patients with differing prognoses and/or response to specific therapies (7). Distinctions between the genetic lesions found in primary and secondary GBMs have been made, with TP53 mutations occurring more commonly in secondary GBMs and EGFR amplifications and ...
There are currently few therapeutic options for patients with pancreatic cancer, and new insights into the pathogenesis of this lethal disease are urgently needed. Toward this end, we performed a comprehensive genetic analysis of 24 pancreatic cancers. We first determined the sequences of 23,219 transcripts, representing 20,661 protein-coding genes, in these samples. Then, we searched for homozygous deletions and amplifications in the tumor DNA by using microarrays containing probes for ~10 6 single-nucleotide polymorphisms. We found that pancreatic cancers contain an average of 63 genetic alterations, the majority of which are point mutations. These alterations defined a core set of 12 cellular signaling pathways and processes that were each genetically altered in 67 to 100% of the tumors. Analysis of these tumors' transcriptomes with next-generation sequencing-bysynthesis technologies provided independent evidence for the importance of these pathways and †To whom correspondence should be addressed.
Medulloblastoma (MB) is the most common malignant brain tumor of children. To identify the genetic alterations in this tumor type, we searched for copy number alterations using high density microarrays and sequenced all known protein-coding genes and miRNA genes using Sanger sequencing in a set of 22 MBs. We found that, on average, each tumor had 11 gene alterations, 5 to 10-fold fewer than in the adult solid tumors that have been sequenced to date. In addition to alterations in the Hedgehog and Wnt pathways, our analysis led to the discovery of genes not previously known to be altered in MBs. Most notably, inactivating mutations of the histone-lysine N-methyltransferase genes MLL2 or MLL3 were identified in 16% of MB patients. These results demonstrate key differences between the genetic landscapes of adult and childhood cancers, highlight dysregulation of developmental pathways as an important mechanism underlying MBs, and identify a role for a specific type of histone methylation in human tumorigenesis.
There is considerable debate about the value of personal genome sequencing (1). In addition to the five individuals whose genomes have been sequenced in their entirety, 68 patients have been evaluated for tumor-specific mutations in all exons of protein coding genes (exomic sequencing). This coincidentally yielded information about germline sequence variations in these individuals (2-4). To explore the utility of such information, we evaluated a pancreatic cancer patient (Pa10) whose tumor DNA had been sequenced in (4). This patient had familial pancreatic cancer, as defined by the fact that his sister also had developed the disease.Among the 20, 661 coding genes analyzed, we identified 15,461 germline variants in Pa10 not found in the reference human genome. Of these, 7318 were synonymous, 7721 were missense, 64 were nonsense, 108 were at splice sites, and 250 were small deletions or insertions (54% in-frame). Past studies have shown that tumors arising in patients with a hereditary predisposition harbor no normal alleles of the responsible gene: one allele is inherited in mutant form, often producing a stop codon, and the other (wild type) allele is inactivated by somatic mutation during tumorigenesis. In Pa10, only three genes met these criteria: SERPINB12, RAGE and PALB2. Of these, we considered PALB2 to be the best candidate because germline stop codons in SERPINB12 and RAGE, but not in PALB2, are relatively common in healthy individuals and because germline PALB2 mutations have previously been associated with breast cancer predisposition and Fanconi anemia(5) although its function is not well understood. Pa10 harbored a germline deletion of 4 bp (TTGT at c.172-175) producing a frameshift at codon 58; the pancreatic cancer that developed in Pa10 had somatically acquired a transition mutation (C to T) at a canonical splice site for exon 10 (IVS10+2).To determine whether PALB2 mutations occur in other patients with familial pancreatic cancer, we sequenced this gene in a cohort of 96 familial pancreatic cancer patients, 90 of which were of Caucasian ancestry. Sixteen of these patients had one first degree relative with pancreatic cancer and 80 had at least two additional relatives, at least one of which was first degree, with the disease. Truncating mutations were identified in three of the 96 patients, each producing a different stop codon (Fig. 1). The average age-of-onset of pancreatic cancer in these families was 66.7 years, similar to the mean age of onset of 65.3 years in the families without PALB2 mutations. We determined the germ-line sequence of an affected brother in one of these kindreds, and he harbored the same stop codon. Truncating mutations in PALB2 are rare in individuals without cancer; none have been reported among 1,084 normal individuals in a previous study using a cohort of similar ethnicity to ours (6). While some families we identified with a PALB2 stop mutation had a history of both breast and pancreatic cancer, breast cancer
Among patients with ESKD and AF on dialysis, apixaban use may be associated with a lower risk of major bleeding compared with warfarin, with a standard 5 mg twice a day dose also associated with reductions in thromboembolic and mortality risk.
Through exomic sequencing of ten hepatitis C virus (HCV)-associated hepatocellular carcinomas (HCC) and subsequent evaluation of additional affected individuals, we discovered novel inactivating mutations of ARID2 in four major subtypes of HCC (HCV-associated HCC, hepatitis B virus (HBV)-associated HCC, alcohol-associated HCC and HCC with no known etiology). Notably, 1 8.2% of individuals with HCV-associated HCC in the United States and Europe harbored ARID2 inactivation mutations, suggesting that ARID2 is a tumor suppressor gene that is relatively commonly mutated in this tumor subtype.
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