To establish the MAFG-AS1/miR-339-5p/CDK2 axis, a positive correlation between MAFG-AS1 and CDK2 expression was observed in 50 paired breast cancer tissues (Figure 5A), which was the same as the gene-related analysis in GEPIA (r = 0.26, p < 0.0001) (Figure 5B). This evidence concerns the gene CDK2 and breast cancer.