Serum miR-133b is a potential novel prognostic biomarker for colorectal cancer

Deregulation of microRNA-133b (miR-133b) has been demonstrated to contribute to the initiation and development of various cancers including colorectal cancer (CRC). However, the correlation between serum miR-133b levels and the prognosis of CRC remains elusive.

A total of 98 CRC patients, 30 patients with precancerous polyps and 40 healthy volunteers were enrolled in this study. Quantitative real-time PCR (qRT-PCR) was performed to measure the serum miR-133b expression level in all the participants. The chi-square test was carried out to compare the categorical variables. Furthermore, survival analysis and cproportional hazards regression model were used to determine the prognostic significance of serum miR-133b in CRC.

Serum miR-133b level was progressively down-regulated from healthy controls, patients with precancerous polyps to CRC patients. CRC patients with higher clinical stage or lymph node metastasis had lower serum miR-133b levels. A positive correlation was found between decreased serum miR-133b levels and distant metastasis, lymph node metastasis and clinical stage. Additionally, CRC patients with high serum miR-203 levels had better 5 year overall survival and relapse free survival rates. Finally, low serum miR-133b level was demonstrated to be an independent risk factor for CRC.

These findings suggest that miR-133b might serve as a novel potential prognostic biomarker for CRC.