Plasma Post-operative miR-21 Expression in the Prognosis of Gastric Cancers

Tumor-associated microRNAs have been detected in serum or plasma, but whether plasma microRNA-21(miR-21) could be a potential circulating biomarker for gastric cancer (GC) prognosis in Chinese is still uncertain.Real-time quantitative reverse transcription PCR (qRT-PCR) was employed in this study to compare the relativeexpression of miR-21 between pre-operative and post-operative paired plasmas from 42 patients with primaryGCs. The results showed that the expression levels of miR-21 in the post-operative plasmas were significantlyreduced by an average of 18.2 times in all patients when compared to the pre-operative plasmas, and by 22.1times in the subgroup of patients without family history, while only 1.76 times in the subgroup of patients witha family history. With respect of clinicopathological characteristics, the plasma miR-21 expression was highlyassociated with differentiation degree and lymph node metastasis rate. The results suggested plasma miR-21could be a novel potential biomarker for GC prognosis and evaluation of surgery outcomes, especially in patientswithout a family history.