engleski

Microsatellite instability analysis in sporadic colon cancer patients in Croatia

Colorectal cancer is a result of accumulation of genetic and epigenetic alterations associated with the transformation of normal colonic epithelium to colon adenocarcinoma. Two major pathways involved in colorectal carcinogenesis, the suppressor and the mutator pathway have been identified, with different clinical behaviors and response to chemotherapy. Approximately 15% of sporadic colorectal carcinomas (CRC) arise from mutator pathway which is characterized by microsatellite instability (MSI) caused by deficient mismatch repair system (MMR) and defects in MMR genes. In this study we have examined the incidence of MSI using the NCI Bethesda panel of microsatellite markers (Bat-25a, Bat-26, D2S123, D5S346 D17S250) in 200 sporadic CRC patients. Analysis was performed using ABIPRISM 310 genetic analyzer. The sample was denoted as MSI high (MSI-H) if two or more of the markers demonstrated instability. The sample was denoted as low microsatellite instability (MSI-L) if only in one of the analyzed markers the MSI was detected. The MSI was detected in 11/200 (5, 5 %) analyzed samples and 8 tumors with MSI-H and 3 tumors with MSI-L were identified, while the remaining tumors showed no instability and were classified as microsatellite stable (MSS). MSI was detected in the following markers: Bat25a in 8 patients, Bat26 in 7 patients, D2S123 in 10 patients, D5S346 in 6 patients and D17S250 in 8 patients. There was no statistically significant correlation between the MSI and clinico-pathological characteristics, although MSI was more frequent in larger, poorly differentiated and advanced stage tumors.

microsatellite instability; colon cancer

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