Measurement Of Prostatic Acid Phosphatase Research Articles

Long-term outcomes after treatment with external beam radiation therapy and palladium 103 for patients with higher risk prostate carcinoma: influence of prostatic acid phosphatase.

The objective of this study was to define the long-term prognostic significance of prostatic acid phosphatase (PAP) levels in patients with higher risk, early-stage prostate carcinoma. One hundred sixty-one consecutive patients with Stage T1-T3 prostate carcinoma (according to the 1992 criteria of the American Joint Committee on Cancer) were treated from 1992 through 1996. Each patient had a Gleason score > or = 7 and/or a prostate specific antigen (PSA) level > 10 ng/mL. The original biopsy slides for 130 of 161 patients were retrieved and rereviewed by a single pathologist (L.T.). Enzymatic PAP measurements were determined using a standard method. Values up to 2.5 Units were considered normal. Patients received 41 grays (Gy) of external beam radiation therapy to a limited pelvic field followed 4 weeks later by a palladium 103 (Pd-103) boost using transrectal ultrasound and fluoroscopic guidance as described previously. The prescribed minimum Pd-103 dose to the prostate was 80 Gy (pre-National Institute of Standards and Technology [NIST]-99). Freedom from biochemical failure was defined as a serum PSA level < or =0.2 ng/mL at last follow-up. There was little correlation between pretreatment PSA levels, Gleason scores, and PAP measurements. Thirty-eight patients developed biochemical failure. The overall actuarial freedom from biochemical progression at 10 years is 79%, with 118 patients followed for > 5 years. In a multivariate Cox proportional hazards analysis that considered each factor as a continuous variable, the strongest predictor of failure was PAP (P = 0.0001), followed by Gleason score (P = 0.13), and PSA (P = 0.04). PAP was especially helpful in stratifying patients with pretreatment PSA levels between 4 ng/mL and 20 ng/mL, for whom the prognosis does not different when they are subdivided into PSA categories. When the PAP subgroup analysis was limited to this relatively favorable group, there was a wide range of prognoses. The biochemical cure rate was remarkably high among the 161 patients evaluated. The fact that the PAP was the strongest predictor of long-term biochemical failure in patients with otherwise higher risk features reported here suggests that it may be a more accurate indicator of micrometastatic disease compared with the Gleason score and the PSA level. This report adds to the rationale for reintroducing PAP measurement into general practice.

Correlation of prostate-specific antigen before prostate cancer detection and clinicopathologic features: evaluation of mass screening populations

Objectives. Although prostate-specific antigen (PSA) has become the reference standard for prostate cancer diagnosis, few reports have examined the long-term changes in PSA values before the diagnosis of prostate cancer in a large number of subjects. We investigated serial PSA levels and related values before prostate cancer diagnosis in a mass screening population and analyzed the values in an attempt to discover some values useful in clinical diagnostic science. Methods. We performed mass screening for prostate cancer in 9671 subjects from 1986 to 1998. The initial screening method was measurement of prostatic acid phosphatase from 1986 to 1991 and measurement of PSA from 1992 to 1998. As a result, 303 cases of prostate cancer were diagnosed. For all the cases diagnosed before 1991, we measured the serum PSA value in preserved frozen serum. Results. The prostate cancer detection rate was 3.1% among all subjects observed during the 13-year period. By measurement of the PSA level using frozen serum during the pre-PSA era, we found that 62% of patients demonstrated a PSA abnormality for more than 1 year (average 2.8) before prostate cancer diagnosis. Prostate cancer that was diagnosed within 1 year after a PSA value became abnormal was not associated with bone metastasis. Concerning the relationship between PSA velocity (PSAV) and clinical stage, the proportion of Stage B cancer was 86% in the subjects whose PSAV level before diagnosis was 0.18 ng/mL/yr or less and it was only 29% in those with PSAV levels of 4.5 ng/mL/yr or more. Only 3 (3.5%) of 86 patients with prostate cancer with PSAV levels of 4.4 ng/mL/yr or less had bone metastasis, and 2 of those 3 patients had poorly differentiated adenocarcinoma. Conclusions. Although a total of 62% of patients had an abnormal PSA level more than 1 year before prostate cancer diagnosis, no patients with prostate cancer who were diagnosed within 1 year after the PSA level became abnormal had bone metastasis. Among patients who have undergone mass screening twice or more, a clinically useful indicator of the lack of bone metastasis would be a period between the detection of PSA levels of 4.1 ng/mL or more but not more than 10 ng/mL and prostate cancer diagnosis of less than 1 year and a diagnosis of well or moderately differentiated adenocarcinoma or a PSAV of 4.4 ng/mL/yr or less and a cancer diagnosis of well or moderately differentiated adenocarcinoma.

Prostate-specific antigen in mass screening for carcinoma of the prostate.

Prostate-specific antigen (PSA) has various advantages over prostatic acid phosphatase (PAP) as a marker for prostate cancer, but its role in prostate cancer mass screening remains controversial. We measured serum PSA in addition to serum PAP determination and digital rectal examination (DRE) in our mass screening program to assess the usefulness of PSA for prostate cancer mass screening. Serum PSA and PAP measurements and DRE were performed in 1249 patients in mass screening for carcinoma of the prostate in 1989 and 1990. Thirteen cancers were diagnosed. We calculated the mean plus standard deviations (2SD) of the PSA and PAP values of men without cancer, and assessed the usefulness of PSA for prostate cancer screening by using these figures as the upper limit of normal. The number positive for PSA, PAP and DRE were 39, 36 and 48, respectively. If our screening had been performed without DRE, three cancers would have remained undetected, and the number would have been the same if performed without PSA. If the screening had been performed without PAP, on the other hand, no cancers would have remained undetected. The sensitivities of PSA and PAP were 54% and 23%, respectively. The screening detection rate with DRE and PSA was 0.88%, and with DRE and PAP was 0.64%. Measurement of serum PSA values with adjustment of the cut-off value was considered more useful than PAP in mass screening for prostate cancer.

Serum prostatic acid phosphatase, gamma-seminoprotein and prostatic specific antigen in hemodialysis patients.

Serum concentrations of prostatic acid phosphatase (PAP), gamma-seminoprotein (gamma-Sm) and prostatic specific antigen (PSA) were measured in 31 hemodialysis patients without clinical signs of malignant disease. PAP, gamma-Sm and PSA levels in serum were not significantly different between control and hemodialysis groups. A significant reduction in these tumor markers was not found after dialysis treatment. This indicates that the measurement of PAP, gamma-Sm and PSA in serum is useful for the detection of prostatic cancer in patients undergoing hemodialysis.

Prostate Specific Antigen and Prostatic Acid Phosphatase for Monitoring Therapy of Carcinoma of the Prostate

Serial serum prostatic acid phosphatase (PAP) and prostate specific antigen (PSA) measurements were performed in 871 patients treated with hormonal combination therapy for stage C (95 patients) or stage D2 (776) prostate cancer for an average followup of 26 months. The relative efficacy of serum PAP and PSA for predicting recurrence of the disease was evaluated by 2 statistical methods at the time of progression as well as 6 and 12 months before clinical relapse of disease using optimized cut-off values of 2.0 and 4.0μg./l. for serum PAP and PSA, respectively. At the time of progression the sensitivity (plus or minus standard deviation) of the 2 tests was estimated at 61.1 ± 3.2% and 86.7 ± 3.1% for PAP and PSA, respectively, while the specificity (plus or minus standard deviation) was calculated at respective values of 79.6 ± 1.3% and 92.4 ± 4.1%. Receiver operating characteristic analysis disclosed a greater accuracy for PSA at 89.2 ± 1.7% versus 78.7 ± 1.6% (plus or minus standard deviation) for PAP. The somewhat lower positive predictive value of the PSA test (81.4% versus 89.6%) is more than compensated by its superior negative predictive value (92.4% versus 79.6%). The present data also show that serum PSA measurements are superior to those of serum PAP for predicting disease recurrence in stages C and D prostate cancer patients treated by combination endocrine therapy and they indicate that measurement of serum PAP does not add significantly to single measurement of serum PSA alone.

福岡県粕屋郡久山町における前立腺集団検診

A mass screening for prostatic cancer was conducted in Hisayama town, Fukuoka Prefecture, Japan from 1988 to 1989. As the primary screening questionnaire survey about urination and measurement of serum prostate specific antigen (PSA) were performed in 789 of the 1025 male residents over 50 years old (77.0%). For the second screening with digital rectal examination and transrectal ultrasonography, 184 subjects (23.3%) were picked up. Prostatic cancer was suspected in 33 (4.2%) of the 134 subjects who actually underwent the second screening examination. Prostatic biopsy and other examinations such as measurement of prostatic acid phosphatase and gamma-seminoprotein, urinalysis and radiographic examination were performed in 26 as the third screening, and prostatic cancer was detected in 5 (0.63%); 3 in stage B and 2 in stage C. Four of the 5 subjects with prostatic cancer had complained no urinary symptoms on questionnaire. Serum PSA was useful for detecting early stage prostatic cancer.

The role of prostatic acid phosphatase in the radiotherapeutic management of adenocarcinoma of the prostate

Between 1965 and 1984, 472 patients treated with external beam radiation therapy (EBRT) for adenocarcinoma of the prostate had pretreatment and follow-up serum prostatic acid phosphatase (PAP) measurements performed by the Roy method. All patients were clinically staged (46 A2, 67 B, and 359 C), and none had hormonal manipulation prior to relapse. Four hundred and twenty-five had pretreatment PAP values in the normal range (0.00 0.80 mIU/ml) and had an actuarial 5-year disease-free survival (DFS) of 67% (A 89%, B 93%, and C 59%). Forty-seven patients had elevated pretreatment PAP values. Three of these patients ha have remained disease free. ?l A3 or B disease, and all The remaining 44 patients were in Stage C and had a 5-year D S of 38%. This was significantly worse than the 59% DFS observed in the normal-PAP Stage C group (p 0.4 but <0.8 (P <O.Ol). In Stage C, tumor grade was found to be correlated with initial PAP values so that the higher the grade, the higher the PAP value and the greater was the incidence of elevated PAP values. Of patients with M. D. Anderson grade 4 lesions 8/33 (24%) had elevated PAP values as compared with only 6/89 (7%) elevated PAP values in patients with M. D. Anderson grade 1 tumors (p <O.OZ). Similarly a PAP <0.4 was found in 55/89 (62%) patients with grade 1 lesions while only lo/33 (30%) patients with grade 4 lesions had such low PAP values (p <O.Ol). When corrected for grade, the prognostic significance of low-normal PAP versus high-normal PAP was lost. However, an elevated PAP value was an independent adverse prognostic factor for patients with intermediate (grades 2-3) or high grade (grade 4) tumors. In grades 2 and 3, patients with elevated PAP values had a 5-year DFS of 29% compared with 57% for those with normal values (p <0.05). Patients with grade 4 tumors and elevated PAP values had a 5-year DFS of 13% versus 28% for patients with normal range PAP (p = N.S. due to small patient numbers). The role of post-treatment follow-up PAP measurements was also investigated. Following EBRT mean PAP values decreased significantly within 1 to 3 months. This was true for patients with normal pretreatment values as well as for patients with elevated initial values. For patients with initially normal PAP, the fall in PAP after treatment was of no prognostic significance. For the group of 47 patients with elevated pretreatment PAP, the initial mean PAP was 2.34 and the mean at 1 to 3 months was 0.64 (p <O.Ol). Of these 47 patients, 35 (74%) achieved normal values within 1 to 9 months after treatment and 9 (19%) did not. Of the 35 patients whose PAP normalized, 18 (51%) subsequently relapsed; of the 9 patients whose PAP did not decrease to normal range, 8 (89%) relapsed (p = 0.04). However, the 51% relapse rate of the group whose values normalized was significantly higher than the 33% relapse rate of patients who started with normal PAP (p = 0.04). We conclude that (1) the incidence of elevated PAP correlates with stage; (2) PAP has no prognostic significance in Stage A2 and B; (3) Stage C patients with higher grade tumors are more likely to have high-normal or elevated PAP; (4) even when corrected for grade elevated PAP in Stage C is an adverse factor; and (5) PAP values tend to fall after EBRT and persistent elevation post-EBRT is an especially adverse factor.

An Evaluation of the Immunochemical Measurement of Prostatic Acid Phosphatase and Prostatic Specific Antigen in Carcinoma of the Prostate

No AccessJournal of Urology1 Feb 1988An Evaluation of the Immunochemical Measurement of Prostatic Acid Phosphatase and Prostatic Specific Antigen in Carcinoma of the Prostate J.K. Siddall, E.H. Cooper, D.W.W. Newling, M.R.G. Robinson, and P. Whelan J.K. SiddallJ.K. Siddall More articles by this author , E.H. CooperE.H. Cooper More articles by this author , D.W.W. NewlingD.W.W. Newling More articles by this author , M.R.G. RobinsonM.R.G. Robinson More articles by this author , and P. WhelanP. Whelan More articles by this author View All Author Informationhttps://doi.org/10.1016/S0022-5347(17)42460-8AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail "An Evaluation of the Immunochemical Measurement of Prostatic Acid Phosphatase and Prostatic Specific Antigen in Carcinoma of the Prostate." The Journal of Urology, 139(2), p. 438 © 1988 by The American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 139Issue 2February 1988Page: 438 Advertisement Copyright & Permissions© 1988 by The American Urological Association Education and Research, Inc.MetricsAuthor Information J.K. Siddall More articles by this author E.H. Cooper More articles by this author D.W.W. Newling More articles by this author M.R.G. Robinson More articles by this author P. Whelan More articles by this author Expand All Advertisement PDF DownloadLoading ...

Diagnosis and staging of prostate cancer.

This paper reviews current concepts and recent advances in the diagnosis and staging of carcinoma of the prostate (CaP). Open perineal biopsy is seldom performed because of unnecessary morbidity and a substantial risk of impotence. Transurethral biopsy is inaccurate in detecting both early CaP and residual Cap following transurethral resection of the prostate. Transrectal needle biopsy is contraindicated because of a high rate of sepsis. Transperineal needle biopsy is accurate, has a low risk of complications, and can be performed in an out-patient setting. Transrectal needle aspiration of the prostate appears very accurate with even less morbidity and may replace core needle biopsy in the future. The staging of CaP includes measurement of prostatic acid phosphatase (PAP), radionuclide bone scan, and pelvic lymphadenectomy. PAP should be measured enzymatically using thymolphthalein monophosphate as the substrate. Patients with elevated serum levels of PAP (0.8 IU/L) generally have advanced disease and are not candidates for radical prostatectomy. Radioimmunoassay measurements of PAP have not proved useful because of low specificity. Prostate specific-antigen (PSA) levels are similar in CaP and BPH, and PSA does not appear useful in either the diagnosis or staging of CaP. PSA is, however, extremely sensitive in detecting residual disease after radical prostatectomy. Alkaline phosphate and other biochemical markers have not been reliable because of low specificity. Flow cytometry is a new technique that may be useful in selecting patients for radical prostatectomy. The value of transrectal ultrasound both in diagnosis and staging remains uncertain. Radionuclide bone scan is extremely accurate in detecting osseous metastasis with a false negative rate of two percent. Pelvic lymphadenectomy with frozen section diagnosis is highly accurate in detecting lymphnode metastases with a false negative rate of three point five percent.

Evaluation of a monoclonal immunoradiometric assay for prostate-specific antigen.

We evaluated the analytical performance of a new monoclonal immunoradiometric assay ("M-PSA") for prostate-specific antigen ("Tandem"; Hybritech Inc.) in comparison with a monoclonal immunoradiometric assay ("M-PAP") for mass measurement of prostatic acid phosphatase ("Tandem") and with a conventional enzyme-activity assay ("E-PAP") for prostatic acid phosphatase (EC 3.1.3.2). For M-PSA, the CVs were 1.3-3.0% within-run and 3.0-4.9% between-run. The minimum detectable mass concentration was 0.10 microgram/L, and linearity extended to 100 micrograms/L. The reference interval for M-PSA in 178 healthy men was 0-2.8 micrograms/L. Serum specimens from men with prostatic disease (primarily prostatic carcinoma and benign prostatic hypertrophy) were assayed by the three methods. Correlation was best between mass measurement (M-PAP) and enzyme activity (E-PAP) for prostatic acid phosphatase (r = 0.958). Results for PSA did not correlate well with those for either M-PAP (r = 0.629) or E-PAP (r = 0.387). PSA was increased in a higher percentage of specimens from men with earlier (clinical stage B) prostatic carcinoma than were results from either assay for PAP.

An Evaluation of the Immunochemical Measurement of Prostatic Acid Phosphatase and Prostatic Specific Antigen in Carcinoma of the Prostate

Serum prostatic specific antigen (PSA) and prostatic acid phosphatase (PAP) were evaluated with double monoclonal radioimmunoassays. In 250 patients with prostatic cancer the normal limits were as follows: PSA 0.1-2.7 ng/ml, and PAP 1.09 +/- 0.45 ng/ml (mean +/- SD). In 91 untreated patients with non-metastatic tumours, 42.8% had PSA greater than 10 ng/ml and 18.6% had PAP greater than 2 ng/ml. In 60 untreated patients with metastatic disease PSA was greater than 10 ng/ml in 91.7%; PAP was greater than 2 ng/ml in 65%. In prolonged remission PSA was generally less than 5 ng/ml and PAP less than 2 ng/ml. Longitudinal studies of 2-4 years showed the independence of these markers and a higher correlation of changes in the PSA level and clinical status than given by parallel PAP measurements. In non-metastatic disease, PSA greater than 10 ng/ml at presentation, with or without a coincidentally raised PAP, carried an increased risk of progression within 2 years.

Distribution of prostatic acid phosphatase isoenzymes in normal and cancerous states

We have studied the IEF (isoelectric focusing) profiles and the sedimentation characteristics of intracellular and secretory prostatic acid phosphatase (PAP) in normal and cancerous states. IEF studies show a similar relative distribution of tartrate inhibitable pI 4.9 (approximately 80%) and 5.6 (approximately 20%) forms of this enzyme in normal as well as cancerous prostate. The same IEF profile is obtained regardless of whether an enzymatic or RIA method is utilized for detection of PAP. Of these two isoenzymes, only the form of pI 4.9 predominates in prostatic and seminal fluids and in Stage IV serum. Sedimentation analysis shows that the purified enzyme is exceptionally stable since it retains an S 20,w 0 value of 5.7 at low concentrations (ng/ml). While only the 5.7S form is observed in normal and cancerous tissues as well as in prostatic fluid, analysis of Stage IV serum reveals an additional form at 8.7S. Control experiments suggest that the 8.7S form is not induced by non-specific association with normal serum proteins or by the inhibitor tartrate. Our results suggest that: (a) of the two major isoenzymes in tissue, only the pI 4.9 isoenzyme predominates in secretion, (b) this relationship of intracellular to secretory forms is unaltered in the transition from normal to cancerous tissue, and (c) the utility of PAP as a tumor marker is derived at least in part by the intrinsic stability of the 5.7S form. The significance of the 8.7S form is unknown at the present time, but it does not distort the clinical (RIA) measurement of PAP in serum.

Radioimmunoassay for prostatic acid phosphatase in early prostatic carcinoma.

A radioimmunoassay procedure has been used to measure prostatic acid phosphatase in the serum of 46 patients with intracapsular carcinoma of the prostate. The results obtained did not differ significantly from those obtained in a control group of similar size. It is concluded that the radioimmunoassay procedure for measurement of prostatic acid phosphatase has no advantage over enzyme activity measurements for the detection of early prostatic carcinoma.

Measurement of prostatic acid phosphatase in serum and bone marrow: radioimmunoassay and enzymic measurement compared.

We quantitated the concentrations of prostatic acid phosphatases (EC 3.1.3.2) in serum and bone-marrow aspirates with three commercial radioimmunoassay kits, and the catalytic activities with a thymolphthalein monophosphate-based enzyme test. The enzyme's immunological activity in serum was compared with its catalytic activity for its potential as a detector of early prostatic cancer and its performance as an early marker of metastatic activity in bone. Neither measurement is useful for detecting early stages of prostatic cancer. The spread of carcinoma to lymph nodes or to bone is detected with greater frequency by radioimmunoassay than by the enzymic test. Radioimmunoassay also detected metastasis to the bone more frequently than did physical methods. Analytical and clinical performance of the four methods is described.

Radioimmunoassay versus counterimmune electrophoresis for measurement of serum prostatic acid phosphatase

Radioimmunoassay (RIA) kits obtained from commercial sources were evaluated and compared with a standard counterimmunoelectrophoretic (CIE) assay for the measurement of prostatic acid phosphatase (PAP) in serum. None of the radioimmunoassays was found to be more sensitive than the CIE assay in detecting elevated serum PAP. Both immunoassays were somewhat more effective clinically in measuring prostatic specific acid phosphatase than an enzyme colorimetric assay. The results obtained by CIE agreed with the results obtained by RIA in 96 per cent of the tests. The number of positive results in patients with confirmed prostate adenocarcinoma increased with disease progression. The low number of positive tests in localized adenocarcinoma (Stages A and B) suggests that neither the CIE nor any RIA procedure is useful for screening unselected populations for adenocarcinoma of the prostate.

Development and evaluation of a new solid-phase direct immunoenzyme assay for prostatic acid phosphatase.

In this assay we used polystyrene-tube-attached rabbit antibodies against prostatic acid phosphatase (PAP) that had been purified to homogeneity from human prostate. The amount of immunoreactive acid phosphatase was determined directly by its enzymic activity in the solid-phase-bound immune complex. The detection limit was 0.05 U/L (0.13 microgram/L), the CVs between 4.3 and 10.8%. Investigating the organ specificity of PAP, we found that some cross-reacting acid phosphatase activity could be so measured in human kidney, leukocytes, and platelets, all of which probably contribute to the circulating "prostatic" acid phosphatase that normally is present in serum. Diurnal and day-to-day variations in serum PAP activity were as much as 100% in healthy subjects. Individuals without prostatic diseases (n = 92) had values for serum PAP activity up to 0.36 U/L (0.94 microgram/L), in an age-independent distribution; patients with benign prostatic hyperplasia (n = 62) showed values up to 0.48 U/L (1.25 micrograms/L). With PAP activity of 0.38 U/L or 1.0 microgram/L (90th percentile of the prostatic group) as the upper limit of "normality," overall sensitivity (stages A-D) for detection of prostatic cancer in 33 essentially untreated patients was 65%. Examples for the followup of therapy of prostatic cancer by measurement of serum PAP with this assay are described.

Comparison of countercurrent immunoelectrophoretic assay with commercial radioimmunoassay kits for measuring prostatic acid phosphatase.

We evaluated and compared five commercial radioimmunoassay kits with a standard counter-immunoelectrophoretic assay for the measurement of prostatic acid phosphatase in serum. Four of the five radioimmunoassays performed as described by the supplier with respect to sensitivity, stability, precision, linearity, analytical recovery, and expected values for the normal male population. None of the radioimmunoassays was more clinically sensitive then the counter-immunoelectrophoretic assay for detecting increased prostatic acid phosphatase in serum. Results obtained by counter-immunoelectrophoretic assay agreed with results obtained by radioimmunoassay in 96% of the tests. The proportion of positive results in patients with confirmed prostatic adenocarcinoma increased with disease progression. The fewer positive tests in localized adenocarcinoma (Stages A and B) suggests that neither the counter-immunoelectrophoretic assay nor the radioimmunoassay procedures are useful for screening unselected populations for adenocarcinoma of the prostate. The high percentage of normal values found in those patients clinically free of disease after treatment is encouraging and supports the use of the prostatic acid phosphatase immunoassays in prospectively monitoring the treatment of prostatic cancer patients.

The evaluation of a new enzyme immunoassay for the measurement of prostatic acid phosphatase

An enzyme immunoassay for prostatic acid phosphatase (PAP) has been assessed. An upper limit of normal is set at 1.8 μg/1. There is a very low incidence of raised levels in chronic disease or cancers other than those of the prostate. Patients with well-controlled prostatic cancer have levels < 1.8 μg/1 and show little variation about their own mean. PAP can rise exponentially with a doubling time of 1–5 months. This assay is unlikely to increase the detection of asymptomatic prostatic cancer as 66% of T 0–2N xM 0 cases had PAP < 1.8 μg/l. The main advantages over routine enzyme assays are its sensitivity and accuracy in the lower range.

Will Prostatic Acid Phosphatase Determination by Radioimmunoassay Increase The Diagnosis of Early Prostatic Cancer?

The determination of serum prostatic acid phosphatase by radioimmunoassay has received considerable attention as a more sensitive and specific test than its measurement by the usual enzymatic assay. It has been suggested that the increased sensitivity of the radioimmunoassay will improve greatly our ability to diagnose prostatic cancer in the early operative stages.Our study compares prostatic acid phosphatase determination by the radioimmunoassay and enzymatic techniques in 56 untreated and treated patients with prostatic cancer. In addition, 22 patients with biopsy-proved benign prostatic hyperplasia also were studied. The radioimmunoassay used was based on antibodies raised against prostatic acid phosphatase highly purified by 2-stage, ion-specific chromatography and isoelectric focusing techniques. The enzymatic assay used thymolphthalein monophosphate as the substrate.The patients were staged on the basis of digital examination, technetium bone scan and pelvic lymphadenectomy. There were 4 patients with stage A, 12 with stage B, 13 with stage C and 27 with stage D disease. The radioimmunoassay showed an elevated prostatic acid phosphatase in 13 per cent of the patients with intracapsular disease (stages A and B) and in 50 per cent of the patients with extracapsular disease (stages C and D). This finding compares with an enzymatic prostatic acid phosphatase elevation in 13 per cent of the patients with intracapsular and 53 per cent of those with extracapsular disease. There were fewer falsely elevated prostatic acid phosphatase levels by radioimmunoassay (2) than by enzymatic assay (6) in the patients with benign prostatic hyperplasia.Our data show that the radioimmunoassay method provides a reliable and specific measurement of prostatic acid phosphatase. However, the radioimmunoassay measurement of prostatic acid phosphatase does not appear to be more effective as a screening aid in the diagnosis of early stages of prostatic cancer and in our study it was no more helpful than the enzymatic assay.

Prostatic acid phosphatase(PAP)測定用RIAキットの比較検討ならびに測定上の問題点について

Measurement of prostatic acid phosphatase (PAP) concentration is useful for the diagnosis and treatment of prostatic cancer. Fundamental studies of measurement of PAP concentration by radioimmunoassay were performed and values determined by three commercially available kits were compared, those are, PAP EIKEN RIA Kit (E kit), RIA Quant P.A.P. (M kit) and GammaDab PAP RIA Kit (C kit). Upper limits of normal PAP concentration were 3 ng/ml by E and M kits and 2 ng/ml by C kits, respectively. The reproducibility and the recovery studies of three kits were satisfactory. However, dilution curve of some patients was not strait. PAP concentration of 27 patients measured by three kits were correlated well to each other, but the discrepancy of values was noticed in high PAP concentrations. PAP concentration measured by RIA is more reliable than that by enzyme immunoassay. When keeping serum samples, the effect of time, temperature and frreze and thawing on PAP values was obvious. It is recomended that serum is separated at 4℃ as soon as possible after collecting blood and kept frozen until use.