Background: Colorectal cancer (CRC) is a common cancer througout the world. Incident rate of CRC is different depending on geographical area. The cause of CRC is multifactrial, including diet, environment and genetic. P53 gene is the most important tumor suppressor gene involved in CRC. This study was designed to detect the P53 exon 6 mutation in the colorectal cancers at Isfahan University of Medical Sciences in 2004-2005.

Materials and Methods: This study was performed on 40 colorectal patients cancer reffering to Isfahan Hospitals from 2004 to 2005. After pathological diagnosis, DNA was extracted by phenol chloroform isoamil alcohol in genetic. Exon 6 of the P53 gene was mutiplied using specific primers in a PCR assay and then the mutations were detected by gel electrophoresis and SSCP analysis.

Results: From 40 specimens, 9 (22.5%) were in the rectum and 31 (77.5%) were in the colon. 7 cases (17.5%) had P53 mutation and 33 cases (82.5%) had no mutation in exon 6.

Conclusions: According to this study exon 6 P53 gene mutation could be considered as a current exon in colorectal cancers in Isfahan.