Imaging, Diagnosis, Prognosis Detection of miR-34a Promoter Methylation in Combination with Elevated Expression of c-Met and b-Catenin Predicts Distant Metastasis of Colon Cancer

Purpose:Here,wedeterminedwhether epigenetic inactivationofmiR-34a andmiR-34b/c genesmay serve as a prognostic marker for distant metastases in colon cancer. Experimental Design: Using a case–control study design of 94 primary colon cancer samples with and without liver metastases, we determined CpG methylation frequencies of miR-34a and miR-34b/c promoters, expression of miR-34a, and its targets c-Met, Snail, and b-catenin and their prognostic value. Results: miR-34a methylation was detected in 45.1% (n 1⁄4 42 of 93) of the samples and strongly associatedwithmetastases to the liver (P1⁄40.003) and lymphnodes (P1⁄40.006).miR-34b/cmethylationwas detected in 91.9% of the samples (n 1⁄4 79/86). A significant inverse correlation between miR-34a methylation and expression of mature miR-34a (P 1⁄4 0.018) was detected. Decreased miR-34a expression was associatedwith upregulation of c-Met, Snail, and b-catenin protein levels (P1⁄4 0.031, 0.132, and 0.004), which were associated with distant metastases (P 1⁄4 0.001, 0.017, and 0.005). In a confounder-adjusted multivariate regression model miR-34a methylation, high c-Met and b-catenin levels provided the most significant prognostic information aboutmetastases to the liver (P1⁄4 0.014, 0.031, and 0.058) andmatched pairs showed a higher prevalence of these risk factors in the samples with distant spread (P1⁄4 0.029). Finally, we obtained statistical evidence indicating that the simultaneous detection of these three markers has the highest prognostic value. Conclusions: Silencing of miR-34a and upregulation of c-Met, Snail, and b-catenin expression is associated with liver metastases of colon cancer. Detection of miR-34a silencing in resected primary colon cancer may be of prognostic value, especially in combination with detection of c-Met and b-catenin expression. Clin Cancer Res; 19(3); 710–20. 2012 AACR.