Abstract: Objective To evaluate the diagnostic value of salivary and plasma miR-21 in patients with esophageal cancer (EC).
Methods Total RNA was extracted from saliva and plasma samples from 50 stage I and 50 stage II patients with EC and 50
healthy controls for measurement of miR-21 levels using qPCR. The diagnostic values of salivary and plasma miR-21 levels
were assessed for stage I, stage II, and stage I+II EC. Results Salivary and plasma miR-21 were significantly higher in the EC
patients than in the control group. The diagnostic sensitivities of plasma miR-21 for stage I, stage II, and stage I+II EC were
96%, 64% and 97%, with specificities of 44%, 84%, and 56%, respectively; the sensitivities of salivary miR-21 were 90%, 88%,
and 89%, respectively, with the same specificities of 64%. Regardless of EC staging, the expression of plasma miR-21 showed a
significant positive correlation with that of salivary miR-21, and their diagnostic values were comparable. Conclusion Both
salivary and plasmatic miR-21 can be sensitive biomarkers for EC, and salivary miR-21 detection has the potential to replace
plasma detection for EC diagnosis.