The suppressive function of miR-138 was found to target enhancer of zeste homolog 2 (EZH2) (Zhang et al., 2013; Si et al., 2017), pyruvate dehydrogenase kinase 1 and G protein-coupled receptor 124 (GPR124) (Gao et al., 2014; Ye et al., 2015), SP1 (Liu et al., 2018), SOX9 (Hu et al., 2017), and cyclin D3 (Huang et al., 2015) to inhibit tumor cell growth and migration. This evidence concerns the gene ADGRA2 and neoplasm.