1. Centro Javeriano de Oncología, Hospital Universitario San Ignacio, Bogotá, Colombia
2. Oficina de Investigaciones, Hospital Universitario San Ignacio, Bogotá, Colombia
3. Pan American Health Organization, Washington DC, USA
4. Facultad de Medicina, Pontifica Universidad Javeriana, Bogotá, Colombia
5. Early Detection, Prevention & Infection Branch, International Agency for Research on Cancer, Lyon, France