Previous studies had documented that miR-138-5p could inhibit the promoter of the epigenetic regulator EZH2 in cancers, nervous system diseases, and obesity [26–28], and we found that miR-138-5p could interact with the 3′UTR of EZH2 and inhibit its expression, thereby suppressing M1 macrophage differentiation but promoting M2 polarization. The gene discussed is EZH2; the disease is cancer.