RESUMO
Las variantes hereditarias representan aproximadamente el 5 por ciento de los casos de cáncer colorrectal. Las formas más frecuentes son la Poliposis Adenomatosa Familiar (PAF) y el Cáncer Colorrectal Hereditario No Polipósico (HNPCC) o Síndrome de Lynch. Esta revisión analiza los genes relacionados, sus mecanismos moleculares y la importancia de los estudios genéticos en el manejo de los pacientes y las familias comprometidas. En la PAl; diferentes mutaciones del gen APC son responsables del desarrollo de cientos de pólipos en colon y recto, y sus manifestaciones extracolónicas como tumores desmoides, pólipos gástricos y duodenales. En el HNPCC, mutaciones principalmente en los genes MLH1, MSH2 Y MSH6 son la causa de tumores en el colon, endometrio, ovario, estómago, urotelio e intestino delgado.
Hereditary variants account for approximately 5 percent of colorectal cancers. Within them, Familiar Adenomatous Polyposis (FAP) and Hereditary Non Polyposis Colorectal Cancer (HNPCC) or Lynch's syndrome are the most frequent. The underlyinggenes and their molecular pathways are reviewed, and the importance of genetic testing for the clinical management of patients and their families is analyzed. In FARmutations on the APC gene are responsible for the development of hundreds of colorectal polyps and extracolonic manifestations such as desmoid tumors, gastric and duodenal polyps. In HNPCC, mutations on MLH1, MSH2 and MSH6 genes are the most frequent causes of colonic, endometrial, ovarian, gastric, urothelial and small bowel tumors.
Assuntos
Humanos , Neoplasias Colorretais Hereditárias sem Polipose/genética , Polipose Adenomatosa do Colo/genética , Predisposição Genética para Doença , MutaçãoRESUMO
Background: First degree relatives of patients with colorectal carcinoma are at a higher risk of having the disease than the general population. Therefore, they should be subjected to screening colonoscopy. Aim: To assess the effectiveness of colonoscopy among first degree relatives of patients with colorectal carcinoma. Material and methods: A free colonoscopy was offered to first degree relatives of patients operated on for colorectal cancer between 1998 and 2000. As inclusion criteria, subjects had to be asymptomatic, older than 40 years or less than 10 years younger than the index case. Each subject was contacted twice, inviting him/her to have a colonoscopy performed. Results: Two hundred forty three relatives were contacted for the study and in 76, a colonoscopy was performed. Among the latter, a neoplasm was found in 13 (17 percent): One adenocarcinoma and 12 adenomas. Three of these lesions were located in the right colon. The main reason given by the 176 subjects that did not agree to have a colonoscopy was lack of interest. Conclusions: Screening colonoscopy is effective to detect adenoma and adenocarcinomaamong first degree relatives of patients with colorectal carcinoma, however only 31 percent of all potential relatives agreed to undergo a colonoscopy.