Wang T J, Hill T M, Sokoloff R L, Frankenne F, Rittenhouse H G, Wolfert R L
Department of Research and Development, Hybritech Incorporated, San Diego, CA 92196, USA.
Prostate. 1996 Jan;28(1):10-6. doi: 10.1002/(SICI)1097-0045(199601)28:1<10::AID-PROS2>3.0.CO;2-S.
Prostate-specific antigen (PSA) is the most important tumor marker for early detection and monitoring of prostate cancer (PCa) patients. PSA is also elevated in many patients with benign prostatic hyperplasia (BPH). The study of the serum PSA forms, free PSA (f-PSA) and PSA complexed with alpha 1-antichymotrypsin (PSA-ACT), may improve the discrimination between PCa and BPH. An immunoassay specific for f-PSA is reported with very low cross-reactivity (0.7%) to PSA-ACT. Serum specimens from BPH and PCa patients (determined by biopsy) with PSA levels from < 1 to > 100 ng/ml were tested. No f-PSA was detected in serum specimens from normal females (N = 50). Low levels (0-0.3 ng/ml) were detected in specimens from healthy males (N = 60). In specimens from PCa and BPH patients, the f-PSA to total PSA ratio (f/t) was found to range from 1% to higher than 60%. While maintaining an 80% sensitivity for cancer, the f/t ratio improved specificity to approximately 80%, as compared to 55% for total PSA alone. The receiver operating characteristics (ROC) curve analysis of the f/t ratio displayed a greater area under the plot (0.84) compared to total PSA alone (0.745). The results demonstrate that the f/t ratio significantly increases specificity for PCa detection compared to total PSA alone, showing the potential clinical value of the f-PSA immunoassay.
前列腺特异性抗原（PSA）是早期检测和监测前列腺癌（PCa）患者最重要的肿瘤标志物。许多良性前列腺增生（BPH）患者的PSA水平也会升高。对血清PSA形式，即游离PSA（f-PSA）和与α1-抗糜蛋白酶结合的PSA（PSA-ACT）的研究，可能会提高PCa和BPH之间的鉴别能力。据报道，一种对f-PSA特异的免疫测定法对PSA-ACT的交叉反应性非常低（0.7%）。对PSA水平在<1至>100 ng/ml之间的BPH和PCa患者（经活检确定）的血清标本进行了检测。正常女性（N = 50）的血清标本中未检测到f-PSA。健康男性（N = 60）的标本中检测到低水平（0 - 0.3 ng/ml）。在PCa和BPH患者的标本中，发现f-PSA与总PSA的比值（f/t）范围为1%至高于60%。在保持对癌症80%敏感性的同时，f/t比值将特异性提高到了约80%，而单独总PSA的特异性为55%。与单独总PSA（0.745）相比，f/t比值的受试者工作特征（ROC）曲线分析显示曲线下面积更大（0.84）。结果表明，与单独总PSA相比，f/t比值显著提高了PCa检测的特异性，显示了f-PSA免疫测定法的潜在临床价值。
