Gong W, et al. - The mRNA expression levels of kallikrein-related peptidase (KLK) 5 in tumor tissue of 138 subjects using quantitative PCR were evaluated by the researchers in order to investigate the KLK5 mRNA expression pattern in tumor tissue of subjects who were from high-grade serous ovarian cancer (a fifth common cause of cancer-related death) stage FIGO III/IV and correlate the KLK5 mRNA levels with clinical outcome. A highly important association between the mRNA expression levels and protein levels of KLK5 in tumor tissues was recognized. The increased KLK5 mRNA expression was notably correlated with diminished progression-free survival (PFS) and not with overall survival (OS). Using The Cancer Genome Atlas, the relationship of KLK5 mRNA expression with PFS was verified in silico. A trend towards statistical significance was exhibited by the KLK5 mRNA values for PFS, whereas residual tumor mass, but not ascites fluid volume, persisted as an independent indicator for both OS and PFS. Hence, the results achieved with a homogenous patient group with all subjects suffering from advanced high-grade serous ovarian cancer supported previous outcomes implying high KLK5 mRNA levels are an unfavorable markers in ovarian cancer.