Epigenetic modification of micro RNA expression in serrated polyp-carcinoma pathway

锯齿状息肉包括无蒂型和传统型锯齿状息肉/腺瘤，是微卫星不稳定性结直肠癌的一个亚类。相反，增生性息肉被认为发展成癌的风险非常低。由于两种息肉具有结构相似性，因此组织学区分有时很困难且存在问题。我们发现microRNA 20、21、93和181 b在锯齿状息肉和增生性息肉中的差异表达。我们进一步表明，错配修复蛋白hMLH 1表达的缺失（可能是基因甲基化的结果）与锯齿状息肉中的microRNA 21和93呈负相关。我们的研究结果指出了这些microRNA在锯齿状息肉发展或进展中的潜在靶向治疗。

Serrated polyp including sessile and traditional serrated polyp/adenoma is a precursor to a subset of microsatellite-unstable colorectal carcinoma. In contrast, hyperplastic polyp is considered to have very low risk of progression to carcinoma. Histological discrimination is sometimes difficult and problematic between two polyps because of both having architectural similarities. We found a differential expression of microRNA 20, 21, 93 and 181b in serrated and hyperplastic polyps. We have further shown that loss of mismatch repair protein hMLH1 expression, probably as a result of gene methylation, is inversely correlated with microRNA 21 and 93 in serrated polyp. Our results point toward a potential target therapy of these microRNA in serrated polyp development or progression.