To further characterize CYB5D2’s involvement in BC pathogenesis, we have determined the DEGs (differentially expressed genes) relevant to CYB5D2 downregulation (−1.5 SD) in both the TCGA-Cell (n = 817)34 and Metabric (n = 2509) datasets within cBioPortal. This evidence concerns the gene CYB5D2 and breast cancer.