Figure 1

Downregulation of miR-198 in colorectal carcinoma (CRC) and its association with poor survival.

(A) Specificity analysis of miR-198 in situ hybridization (ISH) signal in colorectal cancer. A miR-198- specific probe (20 nM)) was used to label miR-198. No signal is seen with the probe having a scrambled sequence (20 nM) and the snRNA U6 (10 nM) ISH signal is in all cells. Representative staining images for miR-198 expression in normal colorectal tissues and CRC tissues are shown (200× magnification). (B) Statistical analysis of miR-198 expression levels identified by ISH in a group of 116 normal and paired CRC tissues. The level of miR-198 was estimated according to signal intensity and compared between normal and cancer tissues. The expression of miR-198 was normalized to that of U6 snRNA (P < 0.0001, paired t-test). (C) qRT-PCR assay showing that miR-198 expression is significantly decreased in a group of 65 CRC tissues when compared to matched normal tissues (P < 0.001, paired t-test). (D) Association between miR-198 expression and survival of CRC patients (7-year follow-up). The CRC patients were stratified according to miR-198 expression level (median split) into high and low groups. Patients expressing low miR-198 levels displayed significantly shorter survival (P = 0.01, Kaplan–Meier survival test).