Institute for Biomedical Informatics, Department of Pathology and Laboratory Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA, Department of Machine Learning, NEC Laboratories America, Princeton, NJ 08540, USA.|Department of Machine Learning, NEC Laboratories America, Princeton, NJ 08540, USA.|Department of Machine Learning, NEC Laboratories America, Princeton, NJ 08540, USA.|Program of Computational Biology and Bioinformatics and Department of Molecular Biophysics and Biochemistry and Department of Computer Science, Yale University, New Haven, CT 06511, USA.