PROS1 and cancer: SERS immunoassay was applied in other studies as well to detect different cancer biomarkers, as a result LOD for Prostate Specific Antigen (PSA): 1.79 fg/mL; α-fetoprotein: 0.46 fg/mL by SiNP@AgNP@SiC substrate [95]; ferritin antigen 0.32 fg/mL by AuNP@SMSiO2 [107]; PSA: 0.46 fg/mL, prostate-specific membrane antigen (PSMA): 1.05 fg/mL, human kallikrein 2: 0.67 fg/mL by SiC@Ag(film)@AgNPs [130] were obtained.