KLK3 and hepatocellular carcinoma: Currently, glycoproteins are the most used cancer biomarkers in the clinic, such as alpha-fetoprotein (AFP) for hepatocellular carcinoma (Leerapun et al., 2007; Cheng et al., 2014), cancer antigen 125 (CA125) for ovarian cancer (Dochez et al., 2019), carcinoembryonic antigen (CEA) for colon cancer (Auclin et al., 2018), and prostate specific antigen (PSA) for prostate cancer (Albertsen, 2018).