October 16, 2013, Shenzhen, China---A Chinese research team composed of Shenzhen Second People's Hospital, BGI and other institutes reports their latest study on bladder cancer genomics that was published online in Nature Genetics. The discoveries were made using whole-genome and exome sequencing technologies and provide evidence that genetic alterations affecting the sister chromatid cohesion and segregation (SCCS) process may be involved in bladder tumorigenesis and open a new way for the treatment of bladder cancer.
Transitional cell carcinoma (TCC) is the most common type of bladder cancer diagnosed, accounting for 90% of all bladder malignancies in North America, South America, Europe, and Asia. It's reported that there were an estimated 386,300 new bladder cancer cases and 150,200 deaths in 2008 alone. And the number was up to 170,000 deaths in 2010. Until now, there has been no complete genomic data available for developing new therapeutic approaches to combat bladder cancer.
To have a deeper understanding of the genetic basis underlying TCC, Chinese scientists conducted exome sequencing on the tumor and matched peripheral blood samples from 99 TCC patients, and identified 1,023 somatic substitutions and 67 indels respectively. They performed whole genome sequencing (WGS) to detect copy number alterations (CNAs) and obtained 4-fold mean haploid coverage for each sample.
After evaluating the genetic alterations or variants, researchers found frequent alterations in two genes, STAG2 and ESPL1, which are associated with the sister chromatid cohesion and segregation (SCCS) process. Among them, STAG2 was particularly notable as to harbor a greater number of nonsynonymous mutations and a higher ratio of nonsynonymous to synonymous mutations. Their study indicated that chromosomal instability and aneuploidy had an influence on bladder cancer, and provided evidence that bladder cancer became the first type of cancer with major genetic lesions in SCCS genes.
Furthermore, researchers detected a recurrent fusion involving two other SCCS-associated genes, FGFR3 and TACC3, by transcriptome sequencing of 42 DNA-sequenced tumors. They suggested that FGFR3/TACC3 is related with bladder tumorigenesis, and the high expression of TACC3 was mediated by transcriptional regulatory elements in the promoter of the fusion partner, FGFR3, not the amplification of TACC3.
Chao Chen, Senior researcher from BGI, said, "This is a great progress for genetic research of bladder cancer. We discovered frequent alterations in STAG2/ESPL1 and recurrent fusion FGFR3-TACC3, which provide evidence that genetic alterations affecting the SCCS process may be involved in bladder tumorigenesis and implicate a novel therapeutic approach for bladder cancer. In addition, the genomic data yielded in this study also lay a solid foundation for our further research on bladder cancer."
BGI was founded in 1999 with the mission of being a premier scientific partner to the global research community. The goal of BGI is to make leading-edge genomic science highly accessible through its investment in infrastructure that leverages the best available technology, economies of scale, and expert bioinformatics resources. BGI, which includes both private non-profit genomic research institutes and sequencing application commercial units, and its affiliates, BGI Americas, headquartered in Cambridge, MA, and BGI Europe, headquartered in Copenhagen, Denmark, have established partnerships and collaborations with leading academic and government research institutions as well as global biotechnology and pharmaceutical companies, supporting a variety of disease, agricultural, environmental, and related applications. BGI has established a proven track record of excellence, delivering results with high efficiency and accuracy for innovative, high-profile research which has generated over 250 publications in top-tier journals such as Nature and Science. These accomplishments include sequencing one percent of the human genome for the International Human Genome Project, contributing 10 percent to the International Human HapMap Project, carrying out research to combat SARS and German deadly E. coli, playing a key role in the Sino-British Chicken Genome Project, and completing the sequence of the rice genome, the silkworm genome, the first Asian diploid genome, the potato genome, and, most recently, have sequenced the human Gut metagenome, and a significant proportion of the genomes for the 1,000 genomes project. For more information about BGI please visit http://www.genomics.cn
Public Communications Officer, BGI
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