Lin Yang et al. designed silver nanoparticles deposited on graphene oxide for ultrasensitive surface-enhanced Raman scattering immunoassay of cancer biomarkers, which made the detection of prostate-specific antigen (PSA) serum samples from prostate cancer patients satisfactory and thereby demonstrating that sensitive enzyme-assisted dissolved AgNPs SERS immunoassays of PSA have potential applications in clinical diagnosis [168]. Here, KLK3 is linked to prostate cancer.