Quality assessment for prostate-specific antigen (PSA) in relation to ERSPC: report of the PSA Committee

OBJECTIVE

To assess the application of a quality control scheme for total prostate-specific antigen (PSA) as used for participants of the European Randomized Study for Screening of Prostate Cancer (ERSPC) during 1996-2002.

METHODS

From 1996, the first complete year being 1997, an external scheme was organized by the Dutch Quality Assessment Foundation especially for the ERSPC. This scheme consists of one control round every 2 months with two different human serum samples and is only meant to compare the recovery of methods. From 1998 an internal scheme was also applied by adding two distinct samples to every round.

RESULTS

Initially there was a wide variation (coefficient of variation of +/- 15% at threshold PSA of 4.0 ng/mL) among all ERSPC participants who were all using the Tandem assay (Hybritech Inc, USA). After introducing the internal scheme the performance of some intra-ERSPC group comparisons for PSA and the introduction of the completely automated Beckman-Access analyser in 2001 there was state-of-the-art precision for PSA of +/- 5% in the 2002 surveys.

CONCLUSIONS

The ERSPC group measurements of PSA have considerably improved since 1996 because of the application of a quality-assessment scheme and with the introduction of complete automation of the PSA assay. Both findings are in line with earlier developments in clinical chemistry.

Randomised controlled short-term intervention pilot study on rye bran bread in prostate cancer

The short-term effects of rye bran bread intake in prostate cancer were investigated. Ten men with conservatively treated prostate cancer were randomised to a daily supplement of 295 g of rye bran bread and eight men to 275 g of wheat bread (control) with similar fibre content for three weeks. Blood samples, ultrasound-guided core biopsies of the prostate, and urine samples were taken. In the rye group, there was a significant increase in plasma enterolactone, and the apoptotic index increased significantly from 2.1% (SD 1.3) to 5.9% (SD 1.8), P<0.005 as measured by a TUNEL index in four cases in the rye group and seven cases in the control group. Besides a significant decrease in weight in both groups, only small changes were observed in plasma concentrations of prostate specific antigen (PSA), circulating sex hormones, excreted oestrogens, insulin-like growth factor (IGF)-I, and in the endothelial fibrinolytical system. High intake of rye bran bread is suggested to increase apoptosis in prostate tumours.

Interrelationships between plasma testosterone, SHBG, IGF-I, insulin and leptin in prostate cancer cases and controls

Despite strong indirect evidence that androgens stimulate prostate cancer development, data from most analytical studies on this association have been negative. To further investigate this issue, we studied the interrelationships between androgenicity and insulin-like growth factor I (IGF-I), insulin and leptin. Within a prospective cohort study, we measured testosterone, sex hormone-binding globulin (SHBG) and IGF-I, IGF-binding protein (IGFBP)-1, IGFBP-3, insulin and leptin, in plasma from 149 cases and 298 controls. Testosterone correlated positively with SHBG, whereas testosterone and SHBG correlated inversely with IGF-I, IGFBP-3, insulin, leptin and body mass index (BMI). Indices of free testosterone showed an inverse linear correlation with leptin (P<0.01), and a strong drop in the 5th quintile of BMI. However, levels of free testosterone showed non-linear relationships over quintiles of insulin and IGF-I, with a significant increase in the second quintile of IGF-I compared with other levels. The absence of an association between plasma levels of androgens and prostate cancer risk in analytical studies, despite the strong indirect evidence of their tumour-stimulating effects, may reflect the complex and mostly inverse associations of androgenicity to IGF-I, insulin and leptin which are hormones that have also been implicated as risk factors for prostate cancer.

Sequential changes in pancreatic markers in acute pancreatitis

BACKGROUND

Trypsinogen activation within acinar cells plays a crucial role in the pathogenesis of acute pancreatitis (AP). Our aim was to characterize temporal changes of trypsinogen-1, trypsinogen-2, complexes of trypsin-1-alpha1-antitrypsin (T1-AAT) and trypsin-2-alpha1-antitrypsin (T2-AAT), trypsinogen activation peptide (TAP) and pancreatic secretory trypsin inhibitor (PSTI) in patients with AP.

METHODS

The study comprised 64 consecutive patients with AP (19 with severe disease) and 32 controls. The concentrations of trypsinogen-1 and -2, PSTI, T1-AAT and T2-AAT were determined by time-resolved immunofluorometric assays (IFMA), and TAP was measured using a competitive enzyme immunoassay from serum and urine.

RESULTS

The concentrations of trypsinogen-1 and -2 in serum reflected similar patterns, but excretion of trypsinogen-1 into urine was markedly lower than that of trypsinogen-2, the concentration of which correlated strongly with disease severity. The concentrations of T1-AAT were no higher in severe AP than in mild AP, while T2-AAT concentrations were significantly higher in severe than in mild disease. PSTI increased over the course of several days, showing strong correlation with disease severity. The concentrations of plasma and urinary TAP decreased rapidly to undetectable levels. During the early phase of AP, TAP correlated with the disease severity in plasma and urine but there was no difference between controls and patients with mild AP.

CONCLUSION

More pronounced changes in trypsinogen-2 and its complex with AAT than in those of trypsinogen-1 were demonstrated, suggesting that trypsinogen-2 might play a more important role in the pathogenesis of AP than earlier believed. Urinary PSTI showed features warranting further investigations as a marker of disease severity.

Collagenases (MMP-1, -8 and -13) and trypsinogen-2 in fluid from benign and malignant ovarian cysts

Proteolytic enzymes, such as matrix metalloproteinases (MMPs) and tumor-associated trypsinogens (TAT), play a pivotal role in tumor invasion and metastasis. Among MMPs, the interstitial collagenases (MMP-1, -8 and -13) can initiate collagenolysis. In this study, we have studied the levels of MMP-1, -8 and -13 in relation to the level of trypsinogen-2 in fluid from benign and malignant ovarian cysts. Elevated MMP-8 levels occur in many ovarian cyst fluids, and high MMP-8 levels are associated with malignancy. The concentrations of trypsinogen-2 correlate with those of MMP-8, but it remains to be shown whether trypsin-2 plays a role as its activator in vivo. The strong expression of MMP-8 over MMP-1 and MMP-13 in malignant ovarian tumors may indicate that MMP-8 participates in the protease cascades associated with the invasiveness of ovarian tumors.

MMP-9 activation by tumor trypsin-2 enhances in vivo invasion of human tongue carcinoma cells

Various human cancer cells express tumor-associated trypsinogen-2 (TAT-2), which can efficiently activate matrix metalloproteinases (MMPs) in vitro. MMP-2 and MMP-9 are particularly associated with the invasive malignant potential of several tumors. To investigate the role of TAT-2 in tumor invasion, we overexpressed TAT-2 in two malignant human squamous cell carcinoma cell lines of tongue and in non-malignant human papilloma virus transformed gingival keratinocytes. The TAT-2 overexpression significantly increased the levels of active MMP-9 in the most malignant cell line. TAT-2-transfected cells intravasated (invaded blood vessels) up to 60% more efficiently than did the control cells in an in vivo chick embryo chorioallantoic membrane invasion model. This increased intravasation was almost completely abolished by a specific tumor-associated trypsin inhibitor (TATI). These results indicate that TAT-2 has a role in the invasive growth of tumors, either alone or in cascade with gelatinases, especially by generating active MMP-9.

Elevated levels of trypsinogen-2 and trypsin-2-alpha1-antitrypsin in sera of infants and children after cardiac surgery

Acute pancreatitis is a known complication of cardiac surgery with cardiopulmonary bypass but amylase is not a reliable marker in infants. We evaluated whether the serum concentrations of trypsinogen-2 and trypsin-2-alpha1-antitrypsin (AAT) can be used to study disturbances in pancreatic function in children and infants undergoing cardiac surgery. The study comprised 21 infants < 1 year and 25 children aged 1-16 years undergoing cardiopulmonary bypass at the Children's Hospital, Helsinki University Central Hospital. Consecutive serum samples were taken before surgery, at 12 h, 1, 2 and 3 days after surgery, and before discharge from the hospital. A moderate increase in trypsinogen-2 and trypsin-2-AAT in serum was found in more than two-thirds of the patients. On day 3, there was a 4.3-fold mean increase (CI 95% 2.8-6.5) in trypsinogen-2 and a 2.4-fold mean increase (CI 95% 1.8-3.1) in trypsin-2-AAT. In 4 patients trypsinogen-2 was elevated by more than 20-fold. One patient had clinical pancreatitis, but there were no clinical signs of pancreatitis in the other three patients. The changes in trypsinogen-2 and trypsin-2-AAT were similar in infants and children. The moderate increase in the serum concentrations of trypsinogen-2 and trypsin-2-AAT after cardiac surgery in the absence of signs of pancreatitis may be due to a subclinical pancreatic disturbance, but it could also be caused by an inflammatory response and expression of extrapancreatic trypsin. Contrary to amylase, trypsinogen-2 is expressed in the pancreas of infants.

CEA, CA 19-9 and CA 72-4 improve the diagnostic accuracy in gastrointestinal cancers

BACKGROUND

CEA, CA 19-9, CA 242 and CA 72-4 are commonly used tumour markers for gastrointestinal malignancies. The advantage of the concomitant use of these markers is under debate.

MATERIALS AND METHODS

Serum concentrations of the markers were measured at the time of diagnosis in 161 patients with benign and 125 with malignant gastrointestinal diseases. Concomitant use of the markers was evaluated in a logistic regression model.

RESULTS

CA 19-9, CA 242 or CA 72-4 showed similar sensitivity of 44% for gastric cancer, whereas CEA was elevated in 25% of the cases. In patients with colorectal cancer, CEA was most frequently elevated (54%), followed by CA 242 (46%), CA 19-9 (36%) and CA 72-4 (25%). High CA 19-9 and CA 242 serum levels were frequent in patients with cholangiocarcinoma (86% and 68%, respectively) and pancreatic cancer (80% and 63%, respectively). In the benign disease group, serum CA 19-9 was most frequently elevated, i.e. in 24%, 25% and 38% of patients with pancreatic, biliary and liver disorders, respectively. The overall accuracy of CEA, CA 19-9, CA 242 and CA 72-4 was 66%, 71%, 71% and 66%, respectively (p > 0.18). When combined in a logistic regression model, CA 72-4, CA 19-9 and CEA provided independent diagnostic information, whereas CA 242 contributed with independent diagnostic information only on excluding CA 19-9. The probability of cancer for each patient, calculated with the model, was applied as a diagnostic test and was compared with the single markers by ROC-curve analysis. The AUC value of the probability index was significantly higher than the values of the different tumour markers.

CONCLUSION

An algorithm based on the combination of CEA, CA 19-9 and CA 72-4 improved the diagnostic accuracy in gastrointestinal tract malignancies compared with these markers alone.

Comparison of urine trypsinogen-2 test strip with serum lipase in the diagnosis of acute pancreatitis

BACKGROUND/AIMS

The accuracy of a new rapid urinary trypsinogen-2 test strip (actim Pancreatitis) was compared with that of serum lipase for detection of acute pancreatitis in patients with acute abdominal pain.

METHODOLOGY

A prospective study was conducted which consisted of 237 consecutive patients with acute abdominal pain admitted to the emergency unit at Helsinki University Central Hospital. The patients were tested on admission with the actim Pancreatitis test strip. Serum amylase, serum lipase, and urine trypsinogen-2 concentrations were also determined quantitatively.

RESULTS

The actim Pancreatitis test strip result was positive in 27 out of 29 patients with acute pancreatitis (sensitivity 93%) and in 16 of 208 patients with non-pancreatic abdominal pain (specificity 92%). This was superior to that of serum lipase (sensitivity 79% and specificity 88%). With a cut-off > 3x the upper reference limit, the sensitivity of serum lipase was only 55% while the specificity was 99%. The high sensitivity for the actim Pancreatitis test strip resulted in a very high negative predictive value of 99%. All six patients with severe acute pancreatitis were detected by the dipstick. With a higher cut-off value (> 3x upper reference limit) for lipase, two patients with severe acute pancreatitis remained undetected. Combining the actim Pancreatitis dipstick with serum lipase a positive predictive value of 94% was obtained.

CONCLUSIONS

Acute pancreatitis can be excluded with a higher probability with the actim Pancreatitis strip than with serum lipase determination, and therefore appears to be more suitable for screening of acute pancreatitis. With its high specificity with a cut-off > 3x the upper reference limit, serum lipase is suitable as a confirmatory test for pancreatitis when a positive dipstick result is obtained.

Serum tumour markers CA 15-3, TPA, TPS, hCGbeta and TATI in the monitoring of chemotherapy response in metastatic breast cancer

The clinical utility of CA 15-3, polypeptide specific antigen (TPS), tissue polypeptide antigen (TPA), human chorionic gonadotropin (hCGbeta) and tumour-associated trypsin inhibitor (TATI) as indicators of chemotherapy response was assessed in advanced breast cancer. Serum was prospectively collected in one center before treatment (after the first course of chemotherapy) and at response evaluation from 57 patients taking part in a multicentre randomized trial comparing docetaxel with sequential methotrexate and 5-fluorouracil in the treatment of advanced breast cancer. The pretreatment levels of the serum markers were not predictors of the later response to treatment. Changes in the TPS level showed the strongest association with clinical response after the first course of chemotherapy and CA 15-3 at the best response evaluation. However, distinct mismatches occurred with every marker. The most problematic error was an increase in marker levels in patients with clinical responses, which might have caused interruption of therapy. This occurred in 8% and 17% of patients after the first course of chemotherapy and in 4% and 17% of patients at the best response evaluation with CA 15-3 and TPS, respectively. Moreover, after the first course of chemotherapy only 39% and 33% of the patients with progressive disease could be identified on the basis of increasing levels of CA 15-3 and TPS. respectively. Later, at clinical disease progression, TPA and TPS were found to be better indicators of disease progression than CA 15-3. In conclusion, changes in CA 15-3 or TPS levels usually correlate with clinical response, but owing to distinct discordances, they should not be used as sole indicators of response to chemotherapy in advanced breast cancer.

The free beta-subunit of human chorionic gonadotropin as a prognostic factor in renal cell carcinoma

The free beta-subunit of human chorionic gonadotropin beta is expressed in several nontrophoblastic tumours and this is usually associated with aggressive disease. Little is known about human chorionic gonadotropin beta expression in renal cancer. We determined the pretreatment levels of human chorionic gonadotropin beta in serum of patients with renal cell carcinoma, and studied whether elevated levels predicted the clinical outcome. Serum samples were collected before surgery from 177 patients with renal cell carcinoma and from 84 apparently healthy controls. Human chorionic gonadotropin beta in serum was measured by a highly sensitive time-resolved immunofluorometric assay. The prognostic value of human chorionic gonadotropin beta, and of usual clinical and pathological variables was analyzed by the Kaplan-Meier method, the log rank test and Cox multiple hazard regression. The serum concentrations of human chorionic gonadotropin beta were increased in 23% of the renal cell carcinoma patients and they were significantly higher in patients with renal cell carcinoma than in controls (P<0.0001). The concentrations did not correlate with clinical stage and histopathological grade, but patients with increased human chorionic gonadotropin beta levels had significantly shorter survival time than those with levels below the median (cut-off 1.2 pmol l(-1), P=0.0029). In multivariate analysis human chorionic gonadotropin beta, tumour stage and grade were independent prognostic variables. The serum concentration of human chorionic gonadotropin beta is an independent prognostic variable in renal cell carcinoma. The preoperative value of human chorionic gonadotropin beta in serum may be used to identify patents with increased risk of progressive disease.

The ISOBM TD-7 Workshop on hCG and related molecules. Towards user-oriented standardization of pregnancy and tumor diagnosis: assignment of epitopes to the three-dimensional structure of diagnostically and commercially relevant monoclonal antibodies directed against human chorionic gonadotropin and derivatives

The ISOBM TD-7 hCG Workshop was established to characterize the molecular epitope structure and specificities of a panel of diagnostically relevant monoclonal antibodies (MAbs) directed against human chorionic gonadotropin (hCG) and its derivatives, and to consider how this information could be used to improve comparability of immunoassay results for these analytes. In this multicenter study, 27 MAbs have been characterized in detail as to their main and fine specificities by direct binding-, competitive- and sandwich-RIA, -ELISA, BIAcore and Western blotting. Antigens used in the study included the upcoming first WHO reference reagents for immunoassay, i.e. nick-free hCG (hCG), nicked hCG (hCGn), hCG alpha-subunit (hCGalpha), hCG beta-subunit (hCGbeta), nicked hCG beta-subunit (hCGbetan), hCG beta-core fragment (hCGbetacf), synthetic peptides of hCGbeta C-terminal peptide (hCGbetaCTP), and homologous hormones, luteinizing hormone (LH) and subunits (LHbeta) from various species. Correct classification of blinded internal controls demonstrated the reliability of the MAb referencing approach. Three-dimensional molecular epitope assignment was possible in many instances by comparing immunoreactivity of the ISOBM MAbs (n = 27) to a large panel of MAbs (n = 18) previously well characterized in the Innsbruck (P.B.) and Paris (J.M.B.) laboratories. All three major antibody specificities (alpha, n = 1; beta, n = 21; alphabeta, n = 5) were represented in the TD-7 MAb panel. HCGbeta MAbs could further be subdivided into (i) those recognizing hCGbeta only (epitopes: beta(6), n = 1; beta(7), n = 2; beta(14), n = 1) and (ii) those recognizing hCGbeta + hCG (beta1, beta2, beta4, beta5, n = 10; beta8 and beta9, n = 9). Members of the latter group were specific either for hCG + hCGbeta + hCGbetacf (beta1, n = 3) or hCG + hCGbeta + hCGbetaCTP (beta8, n = 6; beta9, n = 1) or in addition to hCG + hCGbeta + hCGbetacf recognized hLH/hLHbeta to a minor (beta2, n = 3; beta4, n = 3) or similar degree (beta5, n = 1). Epitopes were (i) located on the first and third loops protruding from the cystine knot of hCGbeta (beta2-beta6, aa hCGbeta20-25 and 68-77), (ii) presumably centered around the knot itself (beta1), or (iii) on hCGbetaCTP (epitope beta8 = hCGbeta141-144, beta9 = hCGbeta113-116). The ISOBM panel of MAbs represents all major epitope specificities suitable for the design of specific sandwich immunoassays. High analyte variability in serum and urine during the course of pregnancy and tumor development favors certain epitope combinations. For routine diagnostic purposes, assays recognizing a broad spectrum of hCG/hCGbeta variants such as hCG + hCGn + hCGbeta + hCGbetan + hCGbetacf + -CTPhCG + -CTPhCGbeta may be useful. Low cross-reactivity against related glycoprotein hormones (e.g. hLH) and their derivatives is mandatory. These criteria are best met by combinations of MAbs directed against epitopes located around the cystine knot (beta1) and against those encompassing the top of loops 1 and 3 on hCGbeta (beta2, beta4). The first WHO reference reagents for immunoassay of hCG and hCG-related molecules being prepared by the IFCC should facilitate characterization of what assays for 'hCG' are measuring. The next step towards improving between-laboratory comparability of measurements of hCG/hCG derivatives in pregnancy and oncology is provided by results of this TD-7 Workshop.

Ratios of IGF-I, IGF binding protein-3, and prostate-specific antigen in prostate cancer detection

Recent studies have suggested that IGF-I and IGF-binding protein (IGFBP)-3, in combination with prostate-specific antigen (PSA), may enhance prostate cancer detection. In this study, we sought to determine the effect on the prediction of future prostate cancer occurrence by incorporating ratios of total and free PSA, IGF-I, IGFBP-3 into PSA testing. Within a population-based prospective cohort study, we investigated the validity (sensitivity and specificity) of plasma concentrations of total and free PSA, IGF-I, and IGFBP-3 and combinations thereof, in 114 cases and 97 controls, in the range of 1.75-13.5 microg/l for PSA, as used by Khosravi et al. (See Ref. 7 ). Validity estimated by the area under the curve in receiver operator characteristics analysis (with 95% confidence interval) for total PSA was 0.78 (range, 0.71-0.84); total/free PSA, 0.69 (range, 0.62-0.76); total PSA/IGF-I, 0.72 (range, 0.65-0.79); free PSA/IGF-I, 0.55 (range, 0.48-0.63); total PSA/IGFBP-3, 0.74 (range, 0.68-0.81); and free PSA/IGFBP-3, 0.57 (range, 0.49-0.64). Analysis of ratios of IGF-I, IGFBP-3, and free and total PSA did not improve validity of PSA testing in the prediction of future occurrence of prostate cancer. It is unlikely that these combinations will improve prostate cancer detection.

Predicting the severity of acute pancreatitis by rapid measurement of trypsinogen-2 in urine

BACKGROUND

Early identification of patients at risk of developing a severe attack of acute pancreatitis (AP) is of great importance because rapid therapeutic interventions improve outcome. At a cutoff of 50 microg/L, trypsinogen-2 measured by a rapid urinary dipstick is a sensitive and specific diagnostic test in AP. The trypsinogen-2 concentration correlates with the severity of the disease, and a test with a higher cutoff might therefore be useful for prediction of disease severity.

METHODS

We increased the detection limit of the urinary trypsinogen-2 test strip (Actim Pancreatitis) from 50 microg/L to 2000 microg/L and evaluated the prognostic value of this test. The results were compared with those obtained with serum C-reactive protein and the acute physiology and chronic health evaluation II (APACHE II) score. The study population consisted of 150 consecutive patients with AP (42 with severe disease).

RESULTS

The sensitivity of the rapid urinary test strip (detection limit, 2000 microg/L) for prediction of severe AP, both on admission and at 24 h, was 62%; specificities were 87% and 85%, respectively, positive predictive values were 65% and 62%, and negative predictive values were 85% and 85%. C-Reactive protein had a sensitivity of only 38% on admission, but at 24 h, it was 83%; specificities were 90% and 70%, respectively, whereas positive predictive values were 59% and 52%, and NPVs were 79% and 91%, respectively. On admission the positive-likelihood ratio for the urinary trypsinogen-2 test strip was 4.8, and at 24 h it was 4.2; for C-reactive protein, the values were 3.7 and 2.7, respectively.

CONCLUSIONS

The urinary trypsinogen-2 dipstick is a simple and rapid method for prediction of severe acute pancreatitis.

Validity of the prostate specific antigen test for prostate cancer screening: followup study with a bank of 21,000 sera in Finland

PURPOSE

We investigate the validity of prostate specific antigen (PSA) as a screening test for prostate cancer.

MATERIALS AND METHODS

A registry of serum samples drawn from 1968 to 1976 from 21,387 men was linked to the Finnish Cancer Registry. During followup from 1968 to 1991, 104 prostate cancers were identified. A matched case control design with incidence density sampling and nested in the serum sample bank was applied, and PSA was assessed.

RESULTS

The estimated sensitivity of the test was 44% and specificity 94% at a cutoff of 4.0 microg./l. in the total material. The sensitivity had improved to 86% in patients diagnosed in 5 years after the sample drawing. The test had a better sensitivity (93%) and specificity (96%) in men younger than 65 years at the time of the sample drawing compared to those older. The sensitivity further improved to 100% with a cutoff of 2.5 microg./l.

CONCLUSIONS

PSA is a valid screening test for prostate cancer, which compares favorably with mammography for breast cancer. However, until an effect on mortality has been shown, routine screening cannot be recommended.

Comparison of HPLC and small column (CDTect) methods for disialotransferrin

BACKGROUND

Current methods for determination of carbohydrate-deficient transferrin (CDT) are based on separation of the CDT fraction by ion-exchange chromatography on minicolumns and quantification by immunoassay. Alternatively, the transferrin isoforms can be separated by HPLC anion-exchange chromatography and quantified by absorbance. This method has been reported to improve the validity of CDT as a marker of chronic alcohol abuse.

METHODS

HPLC on either MonoQ or ResourceQ anion-exchange columns was used to separate and quantify isoforms of transferrin with detection at 460 nm. The result was expressed as the percentage of the disialo form (pI 5.7) of total transferrin (DST). The commercial CDTect assay was used as a comparison method. Serum samples from nondrinkers (n = 57), moderate drinkers (n = 77), and heavy drinkers (n = 139) were analyzed.

RESULTS

In ROC analysis for differentiation between moderate and heavy drinkers, the area under the curve (AUC) for the HPLC method was 0.87 (95% confidence interval, 0.81-0.93), whereas that for CDTect was 0.72 (95% confidence interval, 0.64-0.80). At 90% specificity, the sensitivity of DST was 63% (95% confidence interval, 53-73%) compared with 33% (22-44%) for CDT. The reference interval of the HPLC method was 0.68-1.7%.

CONCLUSIONS

The HPLC anion-exchange method for quantification of CDT provides substantially better separation between moderate and heavy drinkers than the CDTect method.

Expression and regulation of MMP-20 in human tongue carcinoma cells

Human matrix metalloproteinase-20 (MMP-20, enamelysin) fragments the enamel-specific protein amelogenin and has been shown to be synthesized exclusively by odontoblasts and ameloblasts and in certain odontogenic tumors. Here we demonstrate, for the first time, the expression of MMP-20 mRNA and protein in two carcinoma cell lines originating from the tongue. Treatment of the SCC-25 and HSC-3 cells with phorbol 12-myristate 13-acetate (10 nmol/L) up-regulated MMP-20 mRNA and protein expression by up to 1.6-fold, but transforming growth factor beta (10 ng/mL) had no effect. The latent proform of recombinant (r) human MMP-20 was converted by tumor-related trypsin-2. Activated rMMP-20 did not degrade type I or type II collagen, but efficiently hydrolyzed fibronectin, type IV collagen, laminin-1 and -5, tenascin-C, and beta-casein. This implies that MMP-20 not only participates in dental matrix remodeling but is also present in tongue carcinoma cells.

Prostate cancer screening within a prostate specific antigen range of 3 to 3.9 ng./ml.: a comparison of digital rectal examination and free prostate specific antigen as supplemental screening tests

PURPOSE

Performing biopsy in all men with a serum prostate specific antigen (PSA) of 3 to 3.9 ng./ml. increases the sensitivity of prostate cancer screening compared with a PSA cutoff of 4 ng./ml. but decreases specificity and may contribute to over diagnosis. Therefore, we evaluated the detection rate and specificity attributable to digital rectal examination and percent free PSA within the PSA range of 3 to 3.9 ng./ml.

MATERIALS AND METHODS

Serum PSA was determined in 20,716 participants in the Finnish population based screening trial. Supplementary digital rectal examination was offered to men with a PSA of 3 to 3.9 ng./ml. during 1996 to 1998 (protocol 1). Those with a suspicious digital rectal examination finding were referred for biopsy. The screening algorithm was modified by substituting percent free PSA for digital rectal examination with a cutoff of 16% as a biopsy criterion in 1999 (protocol 2). In addition, biopsies were performed in all men with PSA 4 ng./ml. or greater.

RESULTS

A total of 23 cancers (2.9%) were detected by digital rectal examination among 801 men, while percent-free PSA resulted in the diagnosis of 13 cases (4.8%) among 270 men with a PSA of 3 to 3.9 ng./ml. The detection rate of tumors with a Gleason score of 5 or greater increased from 1.6% (13 of 801 cases) to 4.4% (12 of 270) in the modified screening program. The PSA cutoff of 3 ng./ml. alone showed 88.6% and 87.5% specificity in protocols 1 and 2 but specificity increased to 93.3% and 91.7% using digital rectal examination and percent free PSA, respectively.

CONCLUSIONS

Using percent free PSA increased the detection rate of aggressive disease compared with digital rectal examination and provided higher specificity than PSA alone.

Trypsinogen-1, -2 and tumour-associated trypsin-inhibitor in bile and biliary tract tissues from patients with biliary tract diseases and pancreatic carcinomas

The bile concentrations of trypsinogen-1, -2 and tumour-associated trypsin-inhibitor (TATI) were determined in 23 patients with benign biliary tract disease, two with biliary tract cancer, and in 15 with pancreatic cancer. We also examined the trypsinogen and TATI expression by immunohistochemistry in tissue specimens from biliary tract cancer and non-neoplastic extrahepatic biliary tract. High levels of trypsinogen-1, trypsinogen-2, and TATI occur in bile of most patients. In contrast to the trypsinogens, the levels of TATI were significantly higher in patients with malignant disease than in those with benign diseases (p=0.04). There was no significant correlation between trypsinogen-2 and amylase (r=0.13, p=0.40), indicating that the occurrence of trypsinogen in bile is not a result of reflux of pancreatic fluid into the bile duct. Immunohistochemically, trypsinogen-2 was detected in five and TATI in 12 out of 15 non-neoplastic biliary tract specimens, and in four and seven out of 11 cholangiocarcinomas, respectively. High concentrations of trypsinogen-1, trypsinogen-2 and TATI occur in the bile of patients with non-neoplastic and malignant biliary tract disease and in patients with pancreatic cancer. At least part of the trypsinogen-2 and TATI found in bile appears to be derived from the biliary epithelium itself.

Preoperative serum concentration of hCGbeta as a prognostic factor in ovarian cancer

In spite of a gradual improvement, survival in epithelial ovarian cancer is disappointingly low. New therapeutic regimens are emerging, and it would be important to be able to predict the prognosis and to stratify patients for clinical trials before therapy. We have evaluated the prognostic value of the pretreatment serum concentrations of 3 tumor markers. The free beta subunit of human chorionic gonadotropin (hCGbeta), CA125 and tumor-associated trypsin inhibitor (TATI) were measured in pretreatment serum samples from 146 patients treated for ovarian cancer between 1990-1995. The patients were followed up until 1998. Elevated concentrations of hCGbeta, CA125 and TATI were observed in 29%, 79% and 33%, respectively. When tested as single variables in Cox's proportional hazards model, stage, grade, size of residual tumor and hCGbeta (all p < 0.001) and CA125 (p = 0.004) correlated with prognosis. However, when fitted as multiple variables together with stage, grade and age in the same model, hCGbeta (RR = 3.42) stage (RR = 2.77) and grade (RR = 3.80) were the only significant variables. When serum hCGbeta was normal, 5-year survival was 80%, but it was only 22% when hCGbeta was elevated. In patients with stage III or IV and minimal residual disease, 5-year survival was 75% if hCGbeta was normal compared with 0% if hCGbeta was elevated. hCGbeta in serum is a strong independent prognostic factor in epithelial ovarian cancer, and its prognostic value is similar to that of grade and stage. The availability of this marker before surgery could facilitate selection of treatment modalities.

Association of trypsin-2 with activation of gelatinase B and collagenase-2 in human bronchoalveolar lavage fluid in vivo

BACKGROUND

Tissue injury mediated by matrix metalloproteinases (MMPs) is a hallmark of inflammatory lung diseases. Latent secreted proMMPs must be activated to be catalytically competent.

AIM

Our aim was to analyse an involvement of the trypsin-2, trypsin-2-alpha1-proteinase inhibitor (PI) complex and tumour-associated trypsin inhibitor (TATI) in the in vivo activation of proMMP-8, -9 and -2.

METHODS

Concentrations of trypsin-2, trypsin-2-alpha1-PI complex and TATI in bronchoalveolar lavage fluid (BALF) were analysed by immunofluorometry. Molecular forms and expression of trypsin-2 and trypsin-2-alpha1-PI complex were identified by Western immunoblot and immunocytochemistry. Gelatinolytic and collagenolytic activities were measured by substrate-based activity assays.

RESULTS

BALFs from 16 of 43 patients and BALFs from five of 15 healthy controls contained trypsin-2-alpha1-PI complex. TATI was found in all healthy control BALFs (median 0.12 microg/L, range 0.02-0.66 microg/L) whereas 8 of 43 BALFs from patients (median 0, range 0-0.64 microg/L, P = 0.0001) contained TATI. Patient BALFs showed significantly increased activation of MMP-9 and MMP-8 compared with healthy controls. The concentrations of trypsin-2-alpha1-PI complex correlated with the in vivo activation of MMP-9 and -8 (r = 0.68, P = 0.002 and r = 0.61, P = 0.008) but not with the activation of MMP-2 in BALFs.

CONCLUSION

Results show a key role of trypsin-2 in the in vivo activation of proMMP-8 and -9 in inflammatory lung diseases.

Characterization and determination of the complex between prostate-specific antigen and alpha 1-protease inhibitor in benign and malignant prostatic diseases

Prostate-specific antigen (PSA) is a tissue-specific serine protease which forms complexes with protease inhibitors such as alpha 1-antichymotrypsin and alpha 2-macroglobulin. We have studied the interaction between PSA and alpha 1-protease inhibitor (API) in vitro and found that 15% of the added PSA binds to API while the majority of API is cleaved between Met358 and Ser359 when PSA is incubated with a 5-fold excess of API at 37 degrees C for 7 days. The complex between PSA and API (PSA-API) formed in vitro displays the same chromatographic behavior, molecular size and immunoreactivity as endogenous PSA-API occurring in serum, indicating that they are identical. PSA-API can be detected in serum by a time-resolved immunofluorometric assay (IFMA), in which a monoclonal antibody to PSA is used as a catcher and a polyclonal antibody to API labeled with a Eu-chelate is used as a tracer. Purified PSA-API formed in vitro is used as a calibrator. PSA-API in serum represents 1.0-7.9% (median 2.4%) of total PSA (tPSA) in prostate cancer (PCa, n = 82) and 1.3-12.2% (median 3.6%, p < 0.01) in patients with benign prostatic hyperplasia (BPH, n = 66). The IFMA for PSA-API in serum is hampered by a variable background, which is caused by non-specific adsorption of the huge excess of API in serum to the solid phase. The background can be determined by an assay using the same tracer as in the IFMA for PSA-API but PSA-unrelated antibody on the solid phase. The background signal is subtracted from the PSA-API signal. The clinical utility of PSA-API in serum has been evaluated in PSA-positive subjects from the Finnish PCa screening trial. After subtraction of the background, the proportion of PSA-API in relation to tPSA is lower in PCa than in controls, 0.9% vs. 1.6%, respectively (p < 0.001). Logistic regression analysis showed that the concentration of PSA-API was independent of the proportion of free PSA as a diagnostic variable among subjects with a tPSA of 4-10 micrograms/l (p = 0.009). The probability of PCa calculated by logistic regression using the concentration of PSA-API and the proportion of free PSA in serum significantly improved cancer specificity at high sensitivity levels (85-95%) as compared to the proportion of free PSA alone.