Gastric juice microRNA-421 is a new biomarker for screening gastric cancer.

MicroRNA-421 (miR-421) plays crucial roles during carcinogenesis and is a potential tumor marker in the diagnosis of several types of cancers. However, whether miR-421 in gastric juice, which is specific for gastric tissue, can be used as a biomarker for gastric cancer screening is unclear. In the present study, real-time quantitative reverse transcription-polymerase chain reaction was used to analyze miR-421 levels in gastric juice from patients with gastric cancer or benign gastric disease, or normal. A receiver operating characteristic (ROC) curve was constructed to evaluate the diagnostic values. The results showed that gastric juice levels of miR-421 in patients with gastric cancer were significantly different from those in benign gastric diseases (P < 0.001). The area under the ROC curve of miR-421 was up to 0.767 (95 % CI = 0.684-0.850). The levels of miR-421 in gastric juice from gastric patients were not significantly associated with the main clinicopathological factors such as tumor size, Lauren's classification, and Borrmann's classification. For the detection of early gastric cancer, the use of gastric juice miR-421 showed a remarkable improvement compared with the use of serum carcinoembryonic antigen alone. These results indicated that gastric juice miRNAs such as miR-421 are useful biomarkers for screening gastric cancer.