Kolorektal kanserli hastalarda tümör dokusunda mikrosatellit instabilite taranması ve klinik üzerine etkinliği

Amaç: Mikrosatellit instabilite, sporadik kolon kanserlerinin yaklaşık %15’inden sorumlu bir genetik yolaktır. DNA mismatch (hatalı eşleşme) onarım sistemindeki defektlerden dolayı oluşmaktadır. DNA mismatch onarım sistemi hatalı olan kişilerde mikrosatellit instabilite oluşmakta ve mutasyon riski artmaktadır. Tümör süpresör genlerde oluşan bu mutasyonlar başta kolorektal kanser olmak üzere, endometrium kanseri, gastrik kanser vb malignansilerin gelişimine yol açmaktadır. Mikrosatellit instabilite en sık proksimal kolon kanserlerinde saptanmaktadır. Kanser dokularında mikrosatellit instabilite, PCR yöntemi ile saptanabilmektedir. Kliniğimizde tanı koyulan kolorektal kanserli hasta grubumuzda, Mikrosatellit İnstabilitenin klinikopatolojik özellikleri ve prognoz üzerine etkisini araştırmak üzere bir çalışma planladık. Yöntem: Bu çalışmada Çukurova Üniversitesi Tıp Fakültesi Hastanesi’nde tanı almış kolorektal kanserli 50 hastadan elde edilen kanserli parafin doku örneklerinde mikrosatellit instabilite aranmıştır. Bulgular: Parafine gömülü örneklerin PCR yöntemiyle incelenmesi sonucunda hastaların 20’si (%40) mikrosatellit instabil, 30’u (%60) mikrosatellit stabil olarak saptandı. Mikrosatellit instabil olan olgularda, mikrosatellit stabil olgulara göre daha sık oranda tümörlerin proksimal kolonda yerleştiği saptandı (sırasıyla %40’a karşılık %13.3, p<0.05). Mikrosatellit instabil grupla mikrosatelit stabil grup, tanı sırasındaki yaş açısından karşılaştırıldığında, instabil olanlarda tanı sırasındaki yaşın daha küçük olduğu saptandı (sırasıyla 52.2’ye karşılık 61.97 yaş). Sonuç: Mikrosatellit instabil kolorektal tümörlerin klinikopatolojik ve prognostik açıdan mikrosatellit stabil olanlardan farklı olması, ileride bu özelliğin prognostik bir belirteç olarak kullanılabileceğini düşündürmektedir. Konuyla ilgili daha fazla olgu sayılarıyla yeni çalışmalara ihtiyaç vardır.

Anahtar Kelimeler:

Kolorektal Kanser, Mikrosatellit İnstabilite, Prognoz

Microsatellite instability screening and clinical efficacy in tumor tissue in patients with colorectal cancer

Aim: Microsatellite instability is a genetic pathway responsible for approximately 15% of sporadic colon cancers. It is caused by defects in the DNA mismatch repair system. Microsatellite instability occurs in people with a damaged DNA mismatch repair system and the risk of mutation increases. These mutations in tumor suppressor genes cause colorectal cancer development. Microsatellite instability is most commonly detected in proximal colon cancers. Microsatellite instability in cancer tissues can be determined by PCR method. In our group of patients with colorectal cancer, we planned a study to investigate the effect of microsatellite instability on the clinicopathological features and prognosis. Methods: In this study, microsatellite instability was investigated in 50 patients who were diagnosed to have colorectal cancer in Çukurova University Medical Faculty Hospital. Results: Paraffin-embedded specimens were examined by PCR method and 20 (40%) of them were ‘’microsatellite instable’’ and 30 (60%) were ‘’microsatellite stable’’. In cases with microsatellite instability, tumors were found to be more proximal in the proximal colon than in microsatellite stable cases (40% to 13.3%, respectively, p <0.05). The age at the time of diagnosis was found younger in the microsatellite instable group compared to the microsatellite stable group (52.2 versus 61.97 years, respectively). Conclusion: The fact that microsatellite instable colorectal tumors are different from those of microsatellite stable in terms of clinicopathological and prognostic aspects suggests that this feature can be used as a prognostic marker in the future. Further studies with more cases are needed.

Keywords:

Colorectal cancer, microsatellite instability, prognosis,

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