تعيين فراواني نشانگرهاي مونونوكليوتيدي1MSI در بيماران مبتلا به سرطان روده بزرگ غير ارثي

Frequency Determination of MSI Mononucleotide Markers in Sporadic Colorectal Cancer Patients

ناپايداري ماكروساتللايت ها در تكرارهاي متوالي موتيف هاي كوتاه DNA رخ ميدهد كه به علت انباشتگي موتاسيون ها در ژن هاي نقص ترميم جفت شدگي باز ها اتفاق مي افتد.بنابراين ميتواند به عنوان يك ماركر جايگزين براي ارزيابي عملكرد ژن هاي MMR2 در سرطان هاي روده بزرگ باشد.علاوه براين ،MSI نه تنها يك ماركر مناسب جهت غربالگري سرطان روده بزرگ ارثي (HNPCC3) مي باشد،بلكه در 15% از موارد سرطان روده بزرگ غير ارثي نيز قابل بررسي مي باشد .هدف از اين بررسي تعيين فراواني ومطالعه وضعيت 5 ماركر ماكروساتل لايتي مونومورفيك در بيماران سرطان روده بزرگ غير ارثي مي باشد.

Background : Colorectal cancers (CRCs) tumors are diagnosed by microsatellite instability (MSI) due to accumulation of insertion/deletion mutations in tandem repeats of short DNA motifs (1 - 6bp) called microsatellites.Microsatellite instability (MSI) is not only a halkmark marker for screening of hereditary nonpolyposis colorectal cancer(HNPCC),but also a prognostic and predictive marker for sporadic colorectal cancer.Our objective was to determine and study the status of five mononucleotide microsatellite status among Iranian patients with sporadic colorectal cancer . Material and Methods : In the current investigation 80 sporadic CRC patients were evaluated for MSI. The pentaplex panel consisting of 5 quasi mononucleotide microsatellite markers (NR-21,BAT-26,BAT-25,NR-27 and NR-24) was used . Results: Our findings reveals that the NR-21 was the most frequent unnstable marker among the other markers (23%).69.6% of specimens had instability in sporadic colorectal cancer.Furthermore,the frequency of instability BAT-25 was determined in 20% sporadic CRC samples .Interestingly our results demonstrated that the frequency of instability NR-24 was 20% that was so close to istability of BAT-25 Marker. Moreover,percentage of NR-27 was 0% in sporadic CRC.Finally , we could find 6.6% instability for BAT-26 in sporadic cases. Conclusion : It seems that among 5 mononucleotide markers NR-21 was the most useful marker for determining the status of sporadic colorectal cancer.Following NR-21,BAT-25 and NR-24 are the most effective markers.Therefore using a triple panel consisting 3 mentioned MSI markers shoud be more promising markers for identifying MSI status in patients with sporadic colorectal cancer.