IGF2BP3低甲基化与结肠癌组织分化的关系

The relationship between IGF2BP3 hypomethylation with colon tumor differentiation

目的探讨IGF2BP3低甲基化与结肠癌组织分化之间的关系。方法收集2011年3月—8月在我院就诊的结肠癌组织标本41例,其中高分化腺癌19例,中分化腺癌12例,低分化腺癌10例,同时收集结肠炎标本12例作为对照。免疫组化和Western blot检测标本IGF2BP3表达。改进ELISA法检测标本DNA总甲基化水平,甲基化特异性PCR(MS-PCR)检测IGF2BP3甲基化水平。结果免疫组化和Western blot结果示结肠癌组织IGF2BP3表达高于结肠炎组织(P<0.05),低分化结肠癌组IGF2BP3表达水平最高,中、高分化程度间表达无明显差异。结肠癌组基因总甲基化水平和IGF2BP3甲基化水低于结肠炎组(均P<0.05),且随着结肠组织分化程度降低,IGF2BP3甲基化水平依次降低(P<0.05)。结论 IGF2BP3甲基化水平与结肠癌分化程度密切相关,在调控结肠癌组织IGF2BP3表达中具有重要价值。

Objective To investigate the relationship between IGF2BP3 hypomethylation with colon tumor differentia-tion. Methods Tissue samples from 41 colorectal cancer were collected from March 2011 to August 2011 in our hospital, among which 19 cases were well-differentiated adenocarcinoma, 12 cases were of moderately differentiated adenocarcinoma and 10 cases were of poorly differentiated adenocarcinoma. Meanwhile biopsy samples from 12 cases of colonic colitis were collected as a control. The expression of IGF2BP3 was assessed by immunohistochemistry and Western blot. An innovate of ELISA technique was used to examine global methylation levels while IGF2BP3 methylation level was tested by methylation specific PCR technique. Results The expressions of IGFBP3 are higher in all colon cancer groups than that in colitis （P〈0.05）. The expression of IGFBP3 in poorly differentiated adenocarcinoma is higher than that in all the other groups, but there is no significant difference between its expressions in the well differentiated group and in the moderately differentiated adeno-carcinoma group. The global DNA level and IGFBP3 methylation level of every colon cancer group is lower than those in coli-tis （P〈0.05）. Also, a tendency of decreasing global DNA and IGFBP3 methylation status was observed comparing well differ-entiated towards poorly differentiated carcinomas （P〈0.05）. Conclusion IGF2BP3 expression in colorectal cancer is asso-ciated with differentiation of colon cancer tissue. A lower global and IGF2BP3 DNA methylation suggest a worse differentia-tion of colon cancer. DNA hypomethylation may therefore play a regulatory role in the expression of IGF2BP3 in colon cancer tissue.