Kolorektal Kanser Tanisi Konmuş Olgularda ve Birinci Derece Yakinlarinda DNA Hasarinin Araştirilmasi

Objective: Studies in all over the world have reported that genetic susceptibility and environmental factors play an important role in the formation of colorectal cancer. Overall, individuals with incidence of colorectal cancer in the first-degree relatives are about twice as likely to develop colorectal cancer as those without any family history. The rapid increase about the information on molecular and biological characteristics of colorectal cancer has shed light on the pathogenesis of colorectal cancer. Biomarkers are often utilized for the determination of increased risk of cancer. The aim of our study was to investigate the potential DNA damage using by comet assay in peripheral lymphocytes of colorectal cancer patients, their first degree relatives compared with healthy subjects. Methods: Peripheral blood samples were taken from untreated patients diagnosed with colorectal cancer (n=26), their first degree relatives (n=26) and healthy subjects (n=18) were analyzed by comet assay. A total of 50 individual cells were screened per sample (from each slide). The length of the DNA migrated in the comet tail, which is an estimate of DNA damage, was measured with image analysis system. Mean tail %DNA for each cell was calculated as 100-Head %DNA. Each participant was interviewed with a questionnaire which covered a detailed sociodemographic attributes including variables known to induce the comet frequency.  Results: The DNA damage was found significantly higher in colorectal cancer patients and their first degree relatives (respectively 10.45±1.50, 9.83±1.40) as compared with the control group (8.59±0.76) (respectively p <0.001, p <0.01).  Conclusion: I n this study, our results demonstrate that comet assay can be used as a biomarker for detecting DNA damage in patients diagnosed with colorectal cancer and especially in to demonstrate the damage in their first degree relatives. Key words: DNA damage, colorectal cancer, comet assay