KLK4 and neoplasm: A higher proportion of elevated KLK4 expression in tumor tissue was observed in patients with an ascites fluid volume > 500 ml (60%, 32/53; Table 1), compared to those with an ascites fluid volume ≤ 500 ml (42%, 33/78; Table 1), which is in line with previous studies demonstrating high levels of KLK4 protein in the effusion fluid of patients suffering from serous epithelial ovarian cancer [13,33].