KLK3 and prostate carcinoma: In one study, devices were constructed to detect MUC1 released from prostate cancer cells,45 and in a separate study similar devices were used to detect both vascular endothelial growth factor (VEGF) and prostate-specific antigen (PSA).46 In the case of the combined VEGF and PSA sensing platform, both aptamers were modified with methylene blue, so the detection of the two was done sequentially with separate electrodes as opposed to simultaneously.