1. Department of Pathology, University of Chicago, Chicago, IL 60637, USA.
2. Cancer Research Laboratory, University of California, Berkeley, CA 94720, USA.
3. Department of Immunology, Howard Hughes Medical Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
4. Bioinformatics Core, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.