1 Department of Computer Science, Rice University, Houston, Texas, USA.
2 Department of Bioinformatics and Computational Biology, the University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA.
3 Department of Genetics, the University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA.
4 Department of Bioinformatics and Computational Biology, the University of Texas M.D. Anderson Cancer Center, Houston, Texas, USA. KChen3@mdanderson.org.
5 Department of Computer Science, Rice University, Houston, Texas, USA. nakhleh@rice.edu.