(A) Two criteria were used to identify key differentially expressed miRNAs: based on the ANOVA on miRNA expression data, at P < 0.01, 26 miRNA genes showed significant differential expression; and integrating miRNA expression, mRNA expression and miRNA target information, at P < 0.01, six out of the 26 miRNAs showed significant anti-correlation with their potential target genes. As a result, the six miRNAs were defined as key differentially expressed miRNAs related to gastric cancer. (B) The expression fold change of the six miRNAs in the tumor samples related to normal samples.