T40

Abstract

Colon adenocarcinoma is one of the most wide spreading malignant tumors in the world, mortality of which remains high. Estimation of cancer on late stages, absence of prognostic and predictive factors, poor understanding of progression mechanism may lead to elevation of mortality. The aim of investigation was to identify morphologic prognostic factors and their combination for colon adenocarcinoma. For this purpose 776 patients with colon adenocarcinoma with the median age 57.6 years were selected. Receptors for chemokine (CCR10, CXCR4), stem cell marker (ALDH1), ki-67, MSH2, MSH6, MLH1, PMS2 were investigated by immunohistochemistry (IHC). Results of IHC were compared with clinical data. Analysis of 217 colon adenocarcinomas by Ki-67 showed that 86% of cases had high proliferative level (Ki-67>30%), among them 39% of cases had very high level of Ki-67 (>70%). We also analyzed proliferation of stem cells using double IHC stain for ALDH1 and Ki-67. It was shown that ALDH1 positive cells had significantly lower Ki-67 positivity than ALDH1 negative cells (p70% and CXCR470% and Ki-67<30% hadthe 5- year relapse-free survival rates of 32% and in 68%, respectively, with the median survival time of 7 month. IHC study of MSH2, MSH6, PMS2, MLH1 shows that at least lack of one marker always accompanies by microsatellite instability. Mutations of these markers were accompanied by lack of expression in 100% of cases. Thus, according to modern classification of colon cancer grade, we divided 45 cases into low and high grades using only histological criteria and additionally – IHC investigation of MSH2, MSH6, PMS2, MLH1. It was shown that in 9% of cases IHC of these markers prevent incorrect evaluation of cancer grade. Conclusion: immunohistochemical investigation of CXCR4, Ki-67, MSH2, MSH6, PMS2, MLH1 may be additional useful prognostic factors for patients with colon adenocarcinoma.