Stigbrand T, Holmgren P A, Jeppsson A, Damber M G, von Schoultz B
Acta Obstet Gynecol Scand. 1985;64(2):99-103. doi: 10.3109/00016348509154699.
A sensitive catalytic assay for placental alkaline phosphatase (PLAP) was used to quantify enzyme levels in sera from women with malignant gynecological tumors, i.e. cervical carcinoma, ovarian carcinoma and carcinoma of the breast. Values were compared with those of a reference group of 155 healthy individuals. In this group, basic mean levels of the enzyme amounted to 0.06 +/- 0.08 mumoles X min-1 X 1(-1) (mean +/- SD), which corresponds to 0.3 +/- 0.4 ng/ml (mean +/- SD) purified placental alkaline phosphatase. Enzyme levels were not significantly affected by age, whereas sex gave slightly higher values for women in all age groups. This difference was statistically significant (p less than 0.001). The discriminating capacity of PLAP as a tumor marker was analysed with this assay and compared in sensitivity with a radio-immunoassay. A cut-off level of 0.2 mumoles X min-1 X 1(-1), corresponding to 1 ng/ml enzyme protein as measured by the radio-immunoassay, detected 23-68% of the tumor patients, giving false-positive results from the control group in the order of 5%. Corresponding values at a cut-off level of 0.3 mumoles X min-1 X 1(-1) (1.5 ng/ml) gave values 20-44% and 2%, respectively. The present investigation emphasizes that sensitivity in assays of placental alkaline phosphatase, whether catalytic or immunological, must not exceed ng-level.
采用一种灵敏的胎盘碱性磷酸酶（PLAP）催化测定法，对患有恶性妇科肿瘤（即宫颈癌、卵巢癌和乳腺癌）的女性血清中的酶水平进行定量。将这些值与155名健康个体组成的参照组的值进行比较。在该组中，该酶的基础平均水平为0.06±0.08微摩尔×分钟-1×升-1（平均值±标准差），相当于0.3±0.4纳克/毫升（平均值±标准差）的纯化胎盘碱性磷酸酶。酶水平不受年龄的显著影响，而在所有年龄组中，女性的酶水平略高。这种差异具有统计学意义（p＜0.001）。用该测定法分析了PLAP作为肿瘤标志物的鉴别能力，并与放射免疫测定法的灵敏度进行了比较。以0.2微摩尔×分钟-1×升-1的临界值（通过放射免疫测定法测得相当于1纳克/毫升的酶蛋白）检测出23% - 68%的肿瘤患者，对照组的假阳性结果约为5%。在0.3微摩尔×分钟-1×升-1（1.5纳克/毫升）的临界值下，相应的值分别为20% - 44%和2%。本研究强调，无论是催化法还是免疫法测定胎盘碱性磷酸酶，其灵敏度都不得超过纳克水平。
