engleski

Loss of heterozygosity and expression analysis of NF1 gene in sporadic colon cancer

Tumorigenesis of colon cancer is a multistep process of mutation accumulation in a number of oncogenes and tumor suppressor genes. NF1 gene protein, neurofibromin, acts as a tumor suppressor by turning the active form of p21ras into an inactive one. This molecular switch has an important role in the control of the cell cycle and differentiation and the changes in the Ras activity are involved in a number cancers. In this study we investigated the loss of heterozygosity (LOH) of the NF1 gene in 100 sporadic colon cancers. Quantitative RT-PCR was used to determine the NF1 mRNA expression in tumors and corresponding normal tissue. Relative ratio of NF1 type I and II expression was examined as well. LOH was observed in 20, 7% of informative samples. The expression of the specific NF1 mRNA was higher in well differentiated tumors and tumors clasified as Dukes' A. The NF1 type II was dominantly expressed in normal tissue, while the NF1 type I prevailed in tumor samples. The NF1 type I/II ratio increased with the decrease of the tumor differentiation, and from non-invasive to invasive cancer.

colon cancer; NF1 gene; LOH; isoform type I; II expression

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