[1] Univ Penn, Med Ctr, Dept Pathol & Lab Med, Philadelphia, PA 19104 USA
[2] Univ Penn, Med Ctr, Inst Med & Engn, Philadelphia, PA 19104 USA
[3] Univ Penn, Med Ctr, Abramson Family Canc Res Inst, Philadelphia, PA 19104 USA
[4] Haverford Coll, Dept Biol, Haverford, PA 19041 USA
[5] Harvard Univ, Sch Med, Brigham & Womens Hosp, Dept Pathol, Boston, MA 02115 USA