Especially in people without signs or symptoms of tumors, assessing the levels of prostate-specific antigen (PSA) for prostate cancer, cancer antigen 125 (CA125) for ovarian cancer, and alpha-fetoprotein (α-FP) for hepatocellular carcinoma (HCC) is used as a minimally invasive screening test using blood samples [1]. Here, KLK3 is linked to ovarian cancer.