1. Massachusetts General Hospital Cancer Center, Boston, Massachusetts, USA
2. Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
3. Division of Oncology, University of Cape Town, Cape Town, South Africa
4. Groote Schuur Hospital Observatory, Cape Town, South Africa
5. Ocean Road Cancer Institute, Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania
6. Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
7. Beth Israel Deaconess Medical Center Cancer Center, Boston, Massachusetts, USA