ONCOmmunity

Underexpression of miR-126 and miR-20b in hereditary and nonhereditary colorectal tumors.

By: Tatsuro Yamaguchi, Takeru Iijima, Rika Wakaume, Keiichi Takahashi, Hiroshi Matsumoto, Daisuke Nakano, Yujiro Nakayama, Takeo Mori, Shinichiro Horiguchi, Michiko Miyaki

Department of Surgery, Tokyo Metropolitan Cancer and Infectious Diseases Center, Komagome Hospital, Tokyo, Japan.
2014-3-31; doi: 10.1159/000363303

Abstract

Objectives

The aim of the study was to determine the significance of miR-126 and miR-20b in colorectal carcinogenesis.

Methods

We analyzed the expressions of miR-126 and miR-20b in 136 colorectal tumors from 39 microsatellite stable (MSS) tumors, 23 high microsatellite instability (MSI-H) tumors, 16 Lynch syndrome, and 58 familial adenomatous polyposis (FAP) tumors including adenoma, intramucosal carcinoma, and invasive carcinoma.

Results

All four kinds of tumors showed underexpression of both miR-126 and miR-20b. The frequency of miR-126 downregulation was 100.0% in FAP adenomas, 85.7% in FAP intramucosal carcinomas, 78.9% in invasive carcinomas, 81.3% in Lynch syndrome tumors, 68.4% in MSS tumors, and 65.4% in MSI-H tumors. The frequency of miR-20b downregulation was 64.0% in FAP adenomas, 50.0% in FAP intramucosal carcinomas, 73.3% in invasive carcinomas, 62.5% in Lynch syndrome tumors, 79.5% in MSS tumors, and 91.3% in MSI-H tumors. The current study demonstrated underexpression of miR-126 and miR-20b in various types of colorectal cancer. These findings support the hypothesis that angiogenesis results from underexpressions of miR-126 and miR-20b and occurs as an early event in colorectal carcinogenesis.

Conclusions

Underexpression of miR-126 and miR-20b was observed in various types of colorectal cancer, and occurs as an early event of colorectal carcinogenesis in FAP tumors.