Detection of chromosomal anomalies observed in colorectal cancers in Elazığ district

2. ABSTRACT Colorectal cancer is one of the most common malignancies worldwide. Genetic instability may play an important role in the accumulation of the large amount of genetic alterations during the pathogenesis of cancer. There are two major forms of genetic instability in colorectal cancers that are chromosomal instability and microsatellit instability. Chromosomal instability are appeared in 87% of colorectal cancers result in gains and losses of genetic materials. P53 gene deletions have been found in low levels in different studies made in colorectal cancers. This ratio changes among 5-10%. We proposed to define P53 gene deletion in colorectal cancers by Flouresans In Situ Hybridization (FISH). We analyzed a total of 28 cases, including 22 colon cancers, and 6 rectum cancers. Slides were performed using touch preparation protocol from 14 tumoral tissue samples, interphase FISH study is performed using P53 locus specific DNA prob and examined 500 cells for each patient. No change of P53 gene is observed 64% in patients. 7% of cases were obtained the gain of p53 gene and 29% of cases were obtained the allelic lose of p53 gene. We found statistically significant correlation between p53 gene change and cancer phases and between patient ages and p53 gene change. Interphase FISH is a powerful method which could establish gene deletions and gains in cancers. The relation between P53 gene deletion and colorectal cancer is not yet explained. For this reason, further examinations are needed to use of molecular genetic technics and immunohistochemistry in this subject. Key Words: CRC, P53 gene, interphase FISH, P53 locus specific DNA probe, genetic instability, microsatellite instability