MicroRNAs (
miRNAs) have been demonstrated to
play an important
role in
carcinogenesis. Previous studies revealed that
miRNAs are present in
human plasma in a remarkably stable form that is protected from endogenous
RNase activity. In this study, we measured the
plasma expression levels of three
miRNAs (miR-21, miR-27a, and miR-155) to investigate the usefulness of
miRNAs for
gastric cancer detection. We initially examined
plasma miRNA expression levels in a
screening cohort consisting of 15
patients with
gastric cancer and 15 healthy controls from Korean
population, using TaqMan
quantitative real-time polymerase chain reaction. We observed that the expression level of miR-27a was significantly higher in
patients with
gastric cancer than in healthy controls, whereas the miR-21 and miR-155a expression levels were not significantly higher in the
patients with
gastric cancer. Therefore, we further validated the miR-27a expression level in 73 paired
gastric cancer tissues and in a validation
plasma cohort from 35
patients with
gastric cancer and 35 healthy controls. In both the
gastric cancer tissues and the validation
plasma cohort, the miR-27a expression levels were significantly higher in
patients with
gastric cancer. Receiver-operator characteristic (ROC)
analysis of the validation cohort, revealed an area under the
ROC curve value of 0.70 with 75%
sensitivity and 56%
specificity in discriminating
gastric cancer. Thus, the miR-27a expression level in
plasma could be a useful
biomarker for the
diagnosis and/or
prognosis of
gastric cancer.