1. Department of Pathology and IBSAL, University Hospital of Salamanca, University of Salamanca, 37007 Salamanca, Spain
2. Biomedical Research Networking Centers-Oncology (CIBERONC), 28029 Madrid, Spain
3. Department of Pathology, University Hospital of Marqués de Valdecilla, 39008 Santander, Spain
4. Department of Oncology and IBSAL, University Hospital of Salamanca, 37007 Salamanca, Spain
5. Department of Pathology, University Hospital of Zamora, 49071 Zamora, Spain
6. Department of Pathology, Puerto Real University Hospital, 11510 Cadiz, Spain