Resumen

PALACIO RUA, Katherine Andrea et al. Molecular characterization of TP53 tumor suppressor gene in colorectal cancer. Rev Col Gastroenterol [online]. 2013, vol.28, n.4, pp.294-300. ISSN 0120-9957.

Introduction: Colorectal cancer (CRC) is one of the most common malignancies in the world, especially in developed countries. In Colombia, the incidence of CRC ranks fourth in men and women. CRC has great genetic heterogeneity. Purpose: The purpose of this study was to determine the presence of mutations in exons 5 to 8 of the TP53 gene in colorectal tumors by direct sequencing. Patients and Methods: Samples with histopathological diagnoses of sporadic CRC were divided into two groups. Group I included 30 tumor samples from fresh biopsies and Group II included 46 tumor tissue samples embedded in paraffin blocks. Mutational analysis was performed for exons 5 through 8 of the TP53 gene using PCR and direct sequencing.Results: The frequency of TP53 mutations was only 4.4%, and mutations that were detected were nonsense mutations. In addition, two polymorphisms that segregate together were identified. All mutations and polymorphisms were detected in samples from Group I. Most of the samples were in advanced stages of cancer. Conclusions: The low frequency of mutations in TP53 suggests the existence of alterations on other related genetic pathways in colorectal carcinogenesis. These could include MSI pathways, CIN and epigenetics. Such alterations could not be excluded in the samples tested. Molecular studies of tissue samples embedded in paraffin are difficult to analyze genetically. Molecular characterization of CRC is important for determining the spectrum of mutations and molecular variants present in our population

Palabras clave : Colorectal cancer; TP53 gene; genetic heterogeneity; carcinogenesis; genetic instability.

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