To determine if STEAP4 is upregulated in PBMC of human diabetics with diabetic retinopathy, mRNA was isolated from human PBMC (n = 15/group) for qPCR analyses of Ct scores, which were used to equate the STEAP4 fold change using 2−ΔΔCt calculations. Here, STEAP4 is linked to diabetic retinopathy.