Browsing by Author "Chamorro Ortega, María Eugenia"

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    Metilación del gen MLH1 e inestabilidad de microsatélites, una serie de pacientes con cáncer colorrectal
    (Universidad Nacional de Colombia. Facultad de Medicina. Departamento de Morfología. Maestría en Genética Humana, 2010) Chamorro Ortega, María Eugenia; Arteaga, Clara E.
    Observational study of colorectal cancer in a series of 155 patients in Colombia, focused on the role of microsatellite instability and methylation of the MLH1 gene. The thesis is grounded on the high mortality associated with colorectal cancer and on the fact that a minority of cases show clear genetic predisposition whereas most are sporadic. In addition to mutations in tumour‑suppressor genes, epigenetic changes such as hypermethylation of CpG islands in promoter regions may silence DNA mismatch‑repair genes, including MLH1. Formalin‑fixed, paraffin‑embedded tumour samples were analysed to determine the methylation status of the MLH1 promoter by bisulphite‑specific PCR, the immunohistochemical expression of hMLH1, and the pattern of microsatellite instability using a standard panel of markers. These molecular findings were correlated with clinical and histopathological variables such as age, anatomic location, tumour type and grade, lymphocytic infiltrate and mucin production. The results describe the frequency of MLH1 methylation and microsatellite instability in this case series and explore their potential value as prognostic markers and as complementary tools for the management of patients with colorectal cancer.