Plasma microRNA-103, microRNA-107, and microRNA-194 levels are not biomarkers for human diffuse gastric cancer

Diffuse-type gastric cancer (DGC) carries a poor prognosis. Effective screening is one measure that might improve the prognosis of this disease. An E-cadherin/p53 double-conditional knockout (DCKO) mouse line recapitulates human DGC morphologically and molecularly. Three circulating microRNAs (miRNA) (miR-103, miR-107, miR-194) in DCKO mice have been identified as biomarkers for DGC. We sought to evaluate whether these circulating miRNAs could be used for the detection of human DGC. Subjects were 50 patients with DGC. Controls were first-time outpatients at Aichi Cancer Center Hospital, age- and sex-matched, without a cancer diagnosis. Total RNA containing miRNA was extracted from the plasma samples and then reverse-transcribed. The levels of miRNAs in plasma samples were quantitatively determined by real-time RT-PCR. Spiked-in cel-miR-39 was analyzed as a normalization control. Levels of the three plasma microRNA levels in DGC cases with or without an intestinal component were not significantly different from those in control subjects. The areas under the receiver operating characteristic curve of miR-103, miR-107, and miR-194 were 0.548, 0.563, and 0.512, respectively. In contrast to the DCKO mouse model, plasma miR-103, miR-107, and miR-194 levels are not altered in DGC and are not suitable for human DGC screening.