1992–1994: Research Instructor, Department of Microbiology/Immunology, Jefferson Cancer Institute, Thomas Jefferson University, Philadelphia, PA 1994–08/99: Research Assistant Professor, Department of Microbiology/Immunology, Kimmel Cancer Institute, Thomas Jefferson University, Philadelphia, PA 09/99–10/05: Associate Professor, Center for Biotechnology, College of Sciences and Technology, Temple University, Philadelphia, PA 11/05–06/06: Associate Professor, Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, PA 07/2006–pres.: Professor, Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, PA 02/2012–pres.: Professor, Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, PA