Sporadic Colorectal Cancer Microsatellite Instability

Objective To research the relation between Micro satellite instability(MSI) and clinicopathologieal features and prognosis in sporadic coloreetal carcinoma (SCRC). Methods Fifty archival paraffin embedded specimens resected from patients with primary SCRC were examined for MSI using PCR SCP liver nitrate staining analysis and five microsatellite markers (BAT26, TP53PCR15. 1, D188474, D18S69, and D38l300). Results MSI[ at each marker varied in frequency and was observed with at least one locus in 30% (15 cases). Based on the number of markers displaying instability per tumor, SCRC was classified into three groups: high requency MSI tumor(MSI, n=8, 16%);low requency MSI tumor (MSI, n=7,14%) and microsatellite stability tumor (MSS, n=35, 70%).Comparing across the three groups in clinicopathological features, the MSIi tumors were associated with tumor site, age, histologic type and tumor lymphocytic infiltration (1k0. 05),whereas no signification differences were noted between the MSI and MSS group (P >0.05). Furthermore, the three groups were not associated with sex, Dukes stage, lymph node metastasis, depth of invasion, grade and survival rate (P >0. 05). Conclusion The results suggested that the MSIl phenotype cancer is distinct from MSI and MSS phenotype cancer , with no apparent differences between MSI and MSS in clinicopathological features. MSI may not be a indicator of prognosis in SCRC.