At least 11 kallikrein genes or proteins have been found to be overexpressed in EOC; they are hK4 [22], hK5 [23,24], hK6 [25,26], hK7 [27], hK8 [28,29], hK9 [30], hK10 [31-33], hK11 [34-37], hK13 [38,39], hK14 [40,41], and hK15 [42] mRNA or protein in ovarian cancer tissue, cell lines, serum, and tumor ascites fluid (Table 2). Here, KLK4 is linked to ovarian cancer.