miR-421/PDCD4, miR-27a-3p/PD-L1, miR-424/PD-L1, miR-26a-5p/PDCD10 and miR-26b-5p/PDCD10 are other routes of participation of miRNAs in the pathogenesis of breast cancer (Table 4). The gene discussed is CD274; the disease is breast cancer.