Category Archives: Computational Genomics

Sclust paper published on NP

After years fighting, our Sclsut paper published on Nature Protocols finally. Enjoy!

Yupeng Cun, Tsun-Po Yang, Viktor Achter*, Ulrich Lang, Martin Peifer, Copy number analysis and inference of subclonal populations in cancer genomes using Sclust. Nature Protocols, 2018,DOI: 10.1038/nprot.2018.033


Frequent Q&A on Sclust software package uses:

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A new fast method for copy number calling, tissue purity estimating and subclone inferring in cancer genome

Our new methods final launched on Nature Protocols, where we developed a series of methods and related C++/R combined software package,  Sclust(around 1.5Gb,大文件谨慎载). In Sclust, you can do copy number calling, cancer tissue purity estimating and clone and subclone structure inferring from normal-tumor paired whole genome/exon sequencing data.

先总结一下,我们方法的有如下点:

1. 可以准确地做copy number calling, tumor purity estimating,subclonal inferring;

2. subclonal inferring的速度超级快。4000~6000 个SNVs 的 clonal inferring 过程在个人电脑上只需3到5秒。

3. sclust 给出了每个集群的倍数树变异,目前还有少数个软件提供这个功能。

欢迎使用软件,欢迎咨询,欢迎交流。

联系邮件:yp.cun@outlook.com。 下面clonal 推断一些背景。

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Inferring tumour evolution 2 – Comparison to classical phylogenetics

Scientific B-sides

Quick recap: Last time we talked about tumor evolution and I presented a toy example to introduce key concepts. I also introduced the intra-tumor phylogeny problem: Given a sample of the genomes of clones in a tumour, reconstruct its `life history’. This problem consists of two sub-problems: (1)identification of clones, and (2) inferring evolutionary relationships between clones.

This problem falls into the general area of reconstructing phylogenetic trees — so how does inferring clonal trees compare to classical phylogenetic methods?

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Inferring tumour evolution 1 – The intra-tumour phylogeny problem

Scientific B-sides

“Cancer evolves dynamically as clonal expansions supersede one another driven by shifting selective pressures, mutational processes, and disrupted cancer genes. These processes mark the genome, such that a cancer’s life history is encrypted in the somatic mutations present,”

write Nik-Zainal et al in the abstract of their 2012 Cell paper `The life history of 21 breast cancers‘. The key figure of their paper shows a phylogenetic tree of tumor development in a patient. The paper contains lots of computational work on analyzing and interpreting mutations based on deep-sequencing data, but –a big surprised but— the very last step of putting together the tree was done manually. Half the paper is describing the reasoning that Peter Campbell and his group used to condense all the evidence they had gathered from genomic data into the tree – but there is no algorithm.

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A new R package for network-based biomarker discovery released

A new R package, netClass, has been release. netClass integrate network information, such as protein-protein interaction network or KEGG, to mRNA classification, but also incorporate miRNA to mRNA with mi-mRNA interaction network for biomarker discovery. This methods we called stSVM and already published in PloS ONE (Cun et al 2013). Apart from stSVM, we also implement the flowing methods in netClass: 

  1. AEP (average gene expression of pathway), Guo et al., BMC Bioinformatics 2005, 6:58.
  2. PAC (pathway activitive classification), Lee E, et  al., PLoS Comput Biol 4(11): e1000217.
  3. hubc (Hub nodes classification), Taylor et al.(2009) Nat. Biotech.: doi: 10.1038/nbt.152
  4. frSVM (filter via top ranked genes), Cun et al. arXiv:1212.3214 ;  Winter etal., PLoS Comput Biol 8(5): e1002511.
  5. stSVM (network smoothed t-statistic) , Cun et al., PloS One,.

NetClass can be download from souceforg ( http://sourceforge.net/projects/netclassr/) or , CRAN (http://cran.r-project.org/web/packages/netClass/ ). For more detail of netClass, you can refer these four papers: