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Published on: April 11, 2016
VarWalker: personalized mutation network analysis of putative cancer genes from next-generation sequencing data
1Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America ; Center for Quantitative Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America.
Abstract:
A major challenge in interpreting the large volume of mutation data identified by next-generation sequencing (NGS) is to distinguish driver mutations from neutral passenger mutations to facilitate the identification of targetable genes and new drugs. Current approaches are primarily based on mutation frequencies of single-genes, which lack the power to detect infrequently mutated driver genes and ignore functional interconnection and regulation among cancer genes. We propose a novel mutation network method, VarWalker, to prioritize driver genes in large scale cancer mutation data. VarWalker fits generalized additive models for each sample based on sample-specific mutation profiles and builds on the joint frequency of both mutation genes and their close interactors. These interactors are selected and optimized using the Random Walk with Restart algorithm in a protein-protein interaction network. We applied the method in >300 tumor genomes in two large-scale NGS benchmark datasets: 183 lung adenocarcinoma samples and 121 melanoma samples. In each cancer, we derived a consensus mutation subnetwork containing significantly enriched consensus cancer genes and cancer-related functional pathways. These cancer-specific mutation networks were then validated using independent datasets for each cancer. Importantly, VarWalker prioritizes well-known, infrequently mutated genes, which are shown to interact with highly recurrently mutated genes yet have been ignored by conventional single-gene-based approaches. Utilizing VarWalker, we demonstrated that network-assisted approaches can be effectively adapted to facilitate the detection of cancer driver genes in NGS data.
Insights
Identifying cancer driver mutations is crucial for drug discovery. VarWalker, a novel network method, effectively prioritizes infrequently mutated driver genes by analyzing interactions, improving upon single-gene approaches.
Area of Science:
- Genomics
- Bioinformatics
- Cancer Research
Background:
- Interpreting next-generation sequencing (NGS) mutation data requires distinguishing driver from passenger mutations.
- Current methods focusing on single-gene frequencies miss infrequently mutated driver genes and ignore gene interactions.
- Identifying driver mutations is key for targeted therapies and new drug development.
Purpose of the Study:
- To introduce VarWalker, a novel mutation network method for prioritizing driver genes in large-scale cancer mutation data.
- To overcome limitations of single-gene frequency approaches by incorporating functional gene interconnections.
- To enhance the identification of targetable genes and potential new cancer drugs.
Main Methods:
- VarWalker utilizes generalized additive models based on sample-specific mutation profiles.
- It builds on joint frequencies of mutated genes and their interactors identified via Random Walk with Restart in protein-protein interaction networks.
- The method was applied to lung adenocarcinoma and melanoma datasets (>300 tumor genomes).
Main Results:
- VarWalker successfully prioritized well-known, infrequently mutated driver genes by considering their interactions with recurrently mutated genes.
- Consensus mutation subnetworks enriched with cancer genes and pathways were derived for specific cancer types.
- Network-assisted approaches demonstrated effectiveness in detecting cancer driver genes in NGS data.
Conclusions:
- VarWalker offers a powerful network-based approach to identify cancer driver genes from NGS data.
- This method improves upon conventional single-gene analyses by capturing crucial gene network information.
- VarWalker facilitates the discovery of novel, infrequently mutated driver genes for therapeutic targeting.
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