Cáncer hereditario de colon: Aportes del diagnóstico genético molecular / Molecular and genetic studies for hereditary colon cancer in two patients and their families

Background: About 30 percent of cases of colon cancer (CC) have a family history of CC, and only 5 percent are hereditary forms. Hereditary forms have an increased risk of CC and other tumors. Aim: To report the molecular and genetic study in two families with hereditary CC. Material and Methods: Molecular analysis of the adenomatous polyposis coli (APC) gene of familial adenomatous polyposis (FAP), was done in a patient with multiple benign polyps and his children. Molecular analysis was performed for MLH1 gene mutation of hereditary non-polyposis colon cancer (HNPCC) in an asymptomatic patient with family history of multiple cancers and his mother with a confrmed mutation in the MLH1 gene. Results: The patient with FAP had an insertion of 17 base pairs in exon 9 of the APC gene and two of his children had the same mutation. The patient with history of HNPCC did not have the family mutation on MLH1. Conclusions: In the case of FAP, molecular study was performed in his children since manifestations in carriers of the mutation may begin in childhood. If the second patient would have had the mutation, the study of his children could have been postponed until the age of 18, when the risk for CC is increased.

Síndrome de Lynch: Caracterización genético clínica. Caso clínico / Hereditary non-polyposis colorectal cancer: Report of four siblings

Hereditary non-polyposis colorectal cancer (HNPCC) or Lynch Syndrome is an autosomic dominant syndrome involving 596-1096 of colorectal cancer patients. Mutations in MLH1 and MSH2 genes account for most cases. These two genes particípate in the DNA mismatch repair pathway. Therefore mutation carriers show microsatellite instability (MSI) in tumors. This syndrome is characterized by the early development of colorectal cancer (before 50 years) and an increased incidence of cancer in other organs. We report four siblings from a family diagnosed with HNPCC. All of them were subjected to colonic surgery for colorectal cancer Moreover, one patient developed an ampulloma after her colon surgery. The molecular-genetic analysis revealed three brothers with microsatellite instability in the tumor tissue, the absence of the MLH1 protein, and the presence of a germ Une mutation localized in introm 15 ofthe MLH1 gene.