1. Serviço de Anatomia Patológica; Instituto Português de Oncologia Francisco Gentil, Lisboa, Portugal & Instituto de Anatomia Patológica, Faculdade de Medicina de Lisboa; Portugal
2. Lone Star College; Houston
3. Department of Pathology; University of Texas, MD Anderson Cancer Center; Houston Texas 77030
4. Department of Head and Neck Surgery; University of Texas, MD Anderson Cancer Center; Houston Texas 77030