The clinical significance ofmiR-4257 in patients with colorectal cancer (CRC) remains unclear. Here, we investigated the usefulness of measuring miR-4257 levels in the plasma and cancer tissues of patients with CRC, and the function of miR-4257 in CRC cell lines.

miR-4257 levels were measured in the plasma and cancer tissues of patients with CRC using quantitative polymerase chain reaction. The relationships between miR-4257 level and clinicopathological features were examined. Proliferation, transwell, wound healing, and adhesion assays were performed using a miR-4257 mimic and inflammatory cytokines.

Relapse-free survival was significantly lower in patients with high miR-4257 levels in the plasma and cancer tissue (p<0.001 andp=0.016, respectively). High miR-4257 expression was an independent predictive factor for recurrence (p=0.017 and p=0.028). Addition of inflammatory cytokines to CRC and normal cell lines increased the expression of miR-4257 in the cell lines and cell culture medium. Over-expression of miR-4257 in CRC cells increased malignancy, while over-expression in normal cells increased adhesion to CRC cells. The addition of inflammatory cytokines to normal cell lines enhanced adhesion to CRC cell lines.

miR-4257 level in plasma and cancer tissues is a biomarker of disease recurrence in patients with CRC. Moreover, miR-4257 promoted tumour growth and was associated with cancer-induced inflammation.