1. Division of Surgical OncologySanta Rita Hospital/ISCMPAPorto Alegre Brazil
2. Laboratory of Genetic ToxicologyFederal University of Health Sciences of Porto Alegre/UFCSPAPorto Alegre Rio Grande do Sul Brazil
3. Institute of Cardiology of Rio Grande do SulUniversity Foundation of CardiologyPorto Alegre Brazil
4. Division of ColoproctologyISCMPAPorto Alegre Brazil