Korbakis Dimitrios, Gregorakis Alkiviades K, Scorilas Andreas
Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Athens, Athens, Greece.
Clin Chem. 2009 May;55(5):904-13. doi: 10.1373/clinchem.2008.103788. Epub 2009 Mar 19.
Kallikrein 5 (KLK5), a recently cloned member of the kallikrein family, codes for the secreted protein KLK5. Active KLK5 protein has a trypsin activity, and the expression of KLK5 gene seems to be regulated by steroid hormones. We performed an expression analysis and clinical evaluation of the KLK5 gene, at the mRNA level, in prostate needle biopsies.
We examined KLK5 mRNA concentrations in 103 prostate tissue specimens. After testing of RNA quality, cDNA was prepared by reverse transcription. A highly sensitive quantitative real-time PCR (qRT-PCR) method for KLK5 mRNA quantification was developed using the SYBR Green chemistry. GAPDH was used as a housekeeping gene.
Specimens from patients with benign prostatic hyperplasia (BPH) showed higher levels of KLK5 mRNA expression than those from patients with prostate cancer (PCa) (P = 0.024). ROC analysis demonstrated that KLK5 expression had significant discriminatory value between BPH and PCa (AUC 0.64; P = 0.016). KLK5 mRNA expression showed a statistically significant negative correlation with the total PSA serum concentration in the PCa patients (P = 0.003). Early-stage tumors showed higher KLK5 expression than late-stage ones (P = 0.014), whereas KLK5 expression was negatively correlated to Gleason score (P = 0.005).
KLK5 mRNA, analyzed by quantitative PCR in prostate needle biopsies, could be an independent biomarker for the differential diagnosis and prognosis in prostate cancer.
激肽释放酶5（KLK5）是激肽释放酶家族最近克隆出的成员，编码分泌蛋白KLK5。活性KLK5蛋白具有胰蛋白酶活性，且KLK5基因的表达似乎受类固醇激素调控。我们在前列腺穿刺活检组织中，对KLK5基因进行了mRNA水平的表达分析及临床评估。
我们检测了103份前列腺组织标本中KLK5 mRNA的浓度。在检测RNA质量后，通过逆转录制备cDNA。利用SYBR Green化学法建立了一种高度灵敏的定量实时PCR（qRT-PCR）方法用于定量KLK5 mRNA。甘油醛-3-磷酸脱氢酶（GAPDH）用作管家基因。
良性前列腺增生（BPH）患者的标本显示KLK5 mRNA表达水平高于前列腺癌（PCa）患者（P = 0.024）。ROC分析表明，KLK5表达在BPH和PCa之间具有显著的鉴别价值（曲线下面积0.64；P = 0.016）。在PCa患者中，KLK5 mRNA表达与血清总前列腺特异性抗原（PSA）浓度呈统计学显著负相关（P = 0.003）。早期肿瘤的KLK5表达高于晚期肿瘤（P = 0.014），而KLK5表达与Gleason评分呈负相关（P = 0.005）。
通过对前列腺穿刺活检组织进行定量PCR分析的KLK5 mRNA，可能是前列腺癌鉴别诊断和预后评估的独立生物标志物。
