KLK3 and cancer: Recently, PSA specific glycosylation changes have been characterized by mass spectrometry analysis and the levels of α-2,3-linked sialic acids on PSA was significantly different in cancer patients compared to controls, indicating that sialylation of PSA has great potential in discriminating cancer patients from controls, thereby improving prostate cancer diagnosis (Tajiri, et al., 2008; Yoneyama, et al., 2014; Pihikova, et al., 2016).