1. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
2. Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
3. These authors contributed equally to this work.
4. Center for Computational Biology and Bioinformatics and Department of Systems Biology, Columbia University, New York, NY 10027, USA.
5. Whitehead Institute for Biomedical Research, Nine Cambridge Center, Cambridge, MA 02142, USA.
6. Broad Institute, Seven Cambridge Center, Cambridge, MA 02142, USA.
7. Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
8. Dana-Farber Cancer Institute, Boston, MA 02115, USA.