Three dysregulated microRNAs in serum as novel biomarkers for gastric cancer screening.

Gastric cancer (GC) is one of the most threatening diseases. The symptoms of GC are complex and hard to detect, which also contribute to the poor prognosis of GC. Besides, the current diagnosis for GC is expensive and invasive. Thus, a fast, noninvasive biomarker is urgently needed for GC screening. MicroRNAs (miRNAs) are small noncoding RNAs, which are involved in a great variety of pathological processes, particularly carcinogenesis. MiRNAs are stable in gastric juice, plasma as well as serum, which facilitate it to be a promising biomarker for cancer. In this study, we selected three novel miRNAs, i.e., miR-233, miR-16, and miR-100, to investigate their potential diagnostic value in GC screening. A total of 50 GC patients and 47 healthy controls were involved in this study. Blood serum samples were collected; RNAs were extracted and normalized with U6 snRNA as the internal control; qRT-PCR was performed for relative expression of target miRNAs. Levels of miRNAs expression were compared by Student's t test for the comparison between two groups, and one-way ANOVA was used for multiple comparisons. The expression of miR-223, miR-16, and miR-100 was all significantly higher in GC patients than controls (all P < 0.001). All the tested miRNAs were manifested to be valuable biomarkers for GC. Relative expression of these miRNAs was significantly correlated with clinical characteristics of GC patients, such as TNM stage (P = 0.036 for miR-223; P < 0.001 for miR-100), metastatic status (P = 0.045 for miR-223; P = 0.031 for miR-16; P = 0.006 for miR-100), tumor size (P = 0.042 for miR-223; P = 0.031 for miR-16; P < 0.001 for miR-100), and differentiation grade (P = 0.036 for miR-223; P = 0.030 for miR-16; P = 0.034 for miR-100). However, in T classification, which considered both tumor size and direct extent of primary tumor, the difference in target miRNAs expression was not significant. In summary, we confirmed the diagnostic value of serum miR-223, miR-16, and miR-100 in GC. Significantly elevated expression of the three miRNAs was also observed in advanced GC patients, which suggested their availability in cancer staging.