Case Western Reserve University, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, OH 44106, USA.
Urology. 2011 Sep;78(3):601-5. doi: 10.1016/j.urology.2011.03.071. Epub 2011 Jul 23.
To provide preliminary clinical performance evaluation of a novel prostate cancer (CaP) assay, prostate-specific antigen/solvent interaction analysis (PSA/SIA) that focused on changes to the structure of PSA.
Two-hundred twenty-two men undergoing prostate biopsy for accepted clinical criteria at 3 sites (University Hospitals Case Medical Center in Cleveland, Cleveland Clinic, and Veterans Administration Boston Healthcare System) were enrolled in institutional review board-approved study. Before transrectal ultrasound-guided biopsy, patients received digital rectal examination with systematic prostate massage followed by collection of urine. The PSA/SIA assay determined the relative partitioning of heterogeneous PSA isoform populations in urine between 2 aqueous phases. A structural index, K, whose numerical value is defined as the ratio of the concentration of all PSA isoforms, was determined by total PSA enzyme-linked immunosorbent assay and used to set a diagnostic threshold for CaP. Performance was assessed using receiver operating characteristic (ROC) analysis with biopsy as the gold standard.
Biopsies were pathologically classified as case (malignant, n=100) or control (benign, n=122). ROC performance demonstrated area under the curve=0.90 for PSA/SIA and 0.58 for serum total PSA. At a cutoff value of k=1.73, PSA/SIA displayed sensitivity=100%, specificity=80.3%, positive predictive value=80.6%, and negative predictive value=100%. No attempt was made in this preliminary study to further control patient population or selection criteria for biopsy, nor did we analytically investigate the type of structural differences in PSA that led to changes in k value.
PSA/SIA provides ratiometric information independently of PSA concentration. In this preliminary study, analysis of the overall structurally heterogeneous PSA isoform population using the SIA assay showed promising results to be further evaluated in future studies.
提供一种新型前列腺癌（CaP）检测方法——前列腺特异性抗原/溶剂相互作用分析（PSA/SIA）的初步临床性能评估，该方法侧重于 PSA 结构的变化。
在克利夫兰凯斯西储大学医院、克利夫兰诊所和退伍军人管理局波士顿医疗保健系统的 3 个地点，根据公认的临床标准，对 222 名接受前列腺活检的男性进行了研究。在经直肠超声引导活检前，患者接受了数字直肠检查和系统前列腺按摩，随后收集尿液。PSA/SIA 检测法确定了尿液中不同 PSA 同种型群体在 2 个水相之间的相对分配。结构指数 K 通过总 PSA 酶联免疫吸附试验确定，其数值定义为所有 PSA 同种型浓度的比值，并用于设定 CaP 的诊断阈值。使用以活检为金标准的接收者操作特征（ROC）分析评估性能。
活检病理分类为病例（恶性，n=100）或对照（良性，n=122）。ROC 性能显示，PSA/SIA 的曲线下面积为 0.90，血清总 PSA 为 0.58。在 k=1.73 的截止值下，PSA/SIA 的灵敏度为 100%，特异性为 80.3%，阳性预测值为 80.6%，阴性预测值为 100%。在这项初步研究中，我们没有尝试进一步控制患者人群或活检的选择标准，也没有分析导致 k 值变化的 PSA 结构差异的类型。
PSA/SIA 提供了与 PSA 浓度独立的比率信息。在这项初步研究中，使用 SIA 检测法对整个结构上异质的 PSA 同种型群体进行分析，结果显示出有前途的结果，有待进一步在未来的研究中评估。
