Prognostic V alue o f t he H uman K allikrein G ene 1 5 E xpression in O varian C ancer

Purpose: KLK15 is a newly cloned human kallikrein gene. Many kallikreins were found to be differentially expressed in ovarian cancer. Like other kallikreins, KLK15 is regulated by steroid hormones in cancer cell lines. KLK15 is upregulated mainly by androgens and to a lesser extent by progestins. The purpose of this study was to examine the prognostic value of KLK15 in ovarian cancer tissues. Materials and Methods: We studied KLK15 expression by quantitative reverse transcriptase polymerase chain reaction (RT-PCR) in 168 consecutive patients with epithelial ovarian cancer. Ten patients with benign ovarian tumors were also included in the study. An optimal cutoff point equal to the 50th percentile was defined based on the ability of KLK15 to predict progression-free survival and overall survival of the study population. Results: KLK15 expression levels were significantly higher in cancerous tissues compared with benign tumors. Kaplan-Meier survival curves showed that KLK15 overexpression is a significant predictor of reduced progressionfree survival (PFS; P < .001) and overall survival (OS; P < .009). Univariate and multivariate analyses indicate that KLK15 is an independent prognostic factor for PFS and OS. A weak positive correlation was found between KLK15 expression and serum CA-125 levels. Conclusion: KLK15 expression, as assessed by quantitative RT-PCR, is an independent marker of unfavorable prognosis for ovarian cancer. J Clin Oncol 21:3119-3126. © 2003 by American Society of Clinical Oncology.