MicroRNA expression patterns of tumors in early-onset colorectal cancer patients

The expression of microRNAs (miRNAs) may differ in tumors from patients with different ethnic origins and ages. The aims of the present study were to clarify the appropriate alterations of miRNA expression associated with the early stages of carcinogenesis in early-onset Turkish colorectal cancer (CRC) patients and to define specific biomarkers that could be used as new diagnostic and prognostic markers for this population.

The expression profiles of 38 different miRNAs associated with CRC were evaluated using miRNA polymerase chain reaction arrays in tumors and surgical margin tissue samples from 40 sporadic early-onset Turkish CRC patients. The relationships between the miRNA expression profiles and the characteristics of the tumors and patients were evaluated.

The expression of miR-106a was found to be upregulated, and miR-143 and miR-125b levels were found to be downregulated in tumor tissues compared with the normal tissues. The high expression level of miR-106a (2.93-fold; P = 0.031) and low expression level of miR-125b (2.42-fold; P = 0.063) were observed in tumors with lymph node metastases compared with the normal colorectal mucosa samples. However, the deregulation of these miRNAs was not significantly associated with survival (log-rank P > 0.05).

The present results implied that miR-106a and the miR-125b were associated with the formation and invasion of colorectal tumors. Thus, these miRNAs might be used as significant prognostic factors and indicators of early-stage CRC. Further studies and validations are required; these miRNAs may provide novel molecular targets for CRC treatment.