miR-211 regulates the expression of in tumoral metastasis and recurrence in colorectal cancer patients with a gene mutation.

Colorectal cancer (CRC) ranks as the third-leading cause of cancer-associated mortalities in Taiwan. The expression of ribonucleotide reductase M2 () and is associated with tumoral malignancy and progression in several types of cancer. The aim of the present study was to determine the association of with the upstream expression of microRNA ( and the association of expression levels of and with clinical outcomes in patients with CRC. The study consisted of 192 tumor tissue samples obtained from patients with CRC. Immunohistochemistry and direct sequencing of DNA were performed to analyze protein expression and / gene mutations in these samples. The expression level of was detected by reverse transcription-quantitative polymerase chain reaction. The results showed that the expression of was lower and that of was higher in patients with lymph node metastasis, distant metastasis, and late-stage CRC compared with patients without lymph node metastasis, distant metastasis and early-stage CRC. A high expression of in patients had a negative effect on overall survival (OS) and disease-free survival (DFS) in CRC. Positive expression of was detected in tumor tissues, and expression associated with the presence of gene mutation. Furthermore, it was detected that the upstream expression was negatively associated with expression in tumor tissues of patients with CRC. expression was associated with survival and tumoral recurrence in patients with mutations. The present authors suggest that the downregulation of and overexpression of in tumor tissues of patients with CRC could be used to predict metastases and disease prognosis, particularly in patients with gene mutations.