1. Universidade Federal do Paraná (UFPR), Curitiba, PR, Brazil
2. Coloproctology Unit, Hospital de Clínicas, Universidade Federal do Paraná (UFPR), Curitiba, PR, Brazil
3. Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brazil
4. Hospital de Clínicas, Universidade Federal do Paraná (UFPR), Curitiba, PR, Brazil
5. Department of Clinical Pathology, Universidade Federal do Paraná (UFPR), Curitiba, PR, Brazil
6. Department of Surgery, Universidade Federal do Paraná (UFPR), Curitiba, PR, Brazil
7. Department of Internal Medicine, Universidade Federal do Paraná (UFPR), Curitiba, PR, Brazil