Frequency of the correlation between mutation in 7th exon of P53 gene and the prognosis of colorectal cancer

Introduction: Colorectal cancer (CRC) is one of the most prevalent cancers in the world. Genetic disorders and dietary habits play a part in CRC. The most important cancer suppressor gene is P53. Different mutations rates in 7th exon of p53 gene are reported in different areas  which may have a relationship with prognosis of CRC. This study examines the relationship between mutation in 7th exon of P53 gene and the prognosis of CRC.

Materials and Methods: This descriptive analytical study included 80 CRC cases hospitalized in Isfahan between 2003 and 2007. The DNA samples were extracted through phenol chloroform isoamil alcohol. In genetic department of Isfahan medical faculty. The 7th exon of P53 gene was amplified using specific primers in a PCR assay. After that mutation was detected by gel electrophoresis and SSCP analysis. P53 gene expression was detected by immunohistochemical methods. Data was analyzed using chi-square test.

Results: From the total of 80 specimens, 4 (5%) had mutation in 7th exon. The positive specimens demonstrated over expression for p53 gene. There was a significant (p<0/001) relationship between 7th exon mutation and over expression of p53 protein. However, the relationship between stage tumor and mutation in 7th exon of p53 gene was not significant (P>0.05). Two samples with mutations as well as one sample without mutation showed metastases in the liver tissue. The prognosis of CRC was 3 years after diagnosis. And follow-up was less in patients with mutation compared to those without mutation.

Conclusion: The result showed that all mutations in 7th exon of p53 are accompanied by p53 over expression. The mutation in 7th exon of p53 gene is associated with poor prognosis in CRC.