[The biomarkers BNP and NT-proBNP]. / Die Biomarker BNP und NT­proBNP.

The present review of the biomarkers BNP and NT-pro-BNP is published in the series "biomarkers" of the Zentralblatt für Arbeitsmedizin, Arbeitsschutz und Ergonomie, which deals with the increasing use of the determination of specific markers in so-called manager preventive and check-up examinations. In principle, BNP and NT-pro-BNP are fundamentally suitable as markers for diagnosing acute and chronic heart failure and for assessing the course. In this context these show a high sensitivity and specificity.

Comparison of a new microbiological assay with a standard high-performance liquid chromatographic method for determination of vitamin B6 in serum.

BACKGROUND: A high-performance liquid chromatographic (HPLC) assay for vitamin B6 in human serum was compared with a novel microbiological assay (ID-Vit) that uses microtitre plates precoated with a specific microorganism, thus avoiding numerous problems associated with the use of stock cultures utilized by common other microbial assay mit B6. METHODS: Data obtained using HPLC were compared with 1D-Vit results in 170 healthy individuals and in 68 patients with coronary artery disease (CAD, 37 with acute coronary syndrome [ACS], 31 with stable CAD). Regression and Bland-Altman analysis were performed. Homocysteine in CAD patients was measured by HPLC. RESULTS: The ID-Vit assay correlated well with the HPLC assay (Pearson's r = 0.89 [p < 0.0001] in healthy and 0.82 [p < 0.001] in CAD individuals). Bland-Altman analyses revealed good agreement between the results of both methods in both cohorts, with > or = 95% of all values grouping within the lines of agreement. In CAD patients, mean homocysteine values did not differ between stable CAD and ACS and were normal. Thirty-seven percent of CAD patients had estimated glomerular filtration rates (GFR) below 60 mL/min/1.73m2. GFR correlated inversely with homocysteine levels (r = -0.80, p < 0.001) whereas neither HPLC nor ID-Vit values for B6 did. CONCLUSIONS: ID-Vit assay and the HPLC standard are in very good agreement. The new assay can easily be automated and is less laborious than common microbiological assays. The lack of correlation between B6 vitamin and homocysteine can be accounted for by the fact that mean vitamin B6 in our CAD patients was in the normal range and that a relevant percentage of patients had chronic renal disease.

Value of Procollagen Type I Aminoterminal Propeptide in Women with Breast Cancer with regard to Metastases.

Background. The aim of this study was to show the importance of the bone marker procollagen type 1 aminoterminal propeptide (P1NP) in detecting bone metastases in women suffering from breast cancer. We furthermore investigated to what degree P1NP is correlated to the degree of bone metastases, and if P1NP is increased in patients with metastases other than bone. Patients and Methods. We analyzed 80 serum samples of women (17 premenopausal/63 postmenopausal) with breast cancer. Therefore we used a specific immunoassay "ELECSYS 2010" by Roche Diagnostics. We divided our group of patients with regard to menopausal status, sites of metastases and number of bone metastases. Results. As a result we found higher concentrations of P1NP in women with radiologically confirmed bone metastases (median: 125.75 ng/mL) in comparison to the collective without bone involvement (median: 73.61 ng/mL). However, both groups showed values above the applied cutoff values of median 27.8 ng/mL for premenopausal women and median: 37.1 ng/mL for the postmenopausal group due to the fact that all patients had cancer. Furthermore higher P1NP concentrations were found in women with more than 5 sites of bone metastases (median: 183.9 ng/mL) than in patients with only one site of bone metastases (median: 37 ng/mL). Also patients with no bone involvement but other sites of metastases showed quite high P1NP concentrations (median: 73.61 ng/mL). Conclusion. The marker of bone turnover procollagen type 1 aminoterminal propeptide can be considered as a useful tool for estimating the extent of bone involvement and for the detection of bone metastases. P1NP cannot replace conventional methods for detecting bone metastases such as radiological methods but it can help clarify unclear radiological results. This study does not take into account the change of P1NP concentration during the course of therapy.

Alpha-1-Fetoprotein (AFP): international proficiency study with different test systems.

BACKGROUND: The present proficiency study aimed to elucidate the comparability and reliability of test systems for the determination of AFP concentrations. METHODS: 25 laboratories using 8 different commercial test systems used liquid BIOREF-AFP control serum in their routine internal quality control over a period of one year. For statistical analysis the results were collected centrally. RESULTS: The statistical analysis of the test results revealed considerable variation for the different laboratories. The deviations of the mean values of different laboratories from the overall mean value varied between 0.1 and 26.1%, and for most of the laboratories the deviation was round about 10%. The precision of measured values in the individual laboratories was in most cases acceptable: Nevertheless, the coefficients of variation of the individual laboratories ranged from 13 to 16.1%. CONCLUSIONS: In conclusion, this study indicates that AFP results vary between different laboratories albeit an international standard for AFP is available. Therefore, every laboratory should participate in external ring studies and should use a quality control serum independent of the test kit manufacturer for the internal quality control.

Value of TRAcP 5b as a diagnostic marker for detection of bone metastases in patients with breast cancer.

BACKGROUND/AIMS: The aim of the study was to test the bone resorption marker TRAcP 5b regarding its suitability for detection of bone metastases in breast cancer patients. PATIENTS AND METHODS: Serum samples from a total of 101 patients with histologically proven breast cancer and from 100 healthy probands were analyzed. The patients were divided into three groups: eight patients without osseous involvement, 65 patients with untreated bone metastases, 28 patients whose bone metastases were treated with bisphosphonate therapy. RESULTS: The TRAcP 5b concentration was significantly higher in breast cancer patients compared to healthy probands. It was not possible to demonstrate a statistically significant difference in the TRAcP 5b concentration if osseous metastases in breast cancer patients were present or not. CONCLUSION: Our research cannot support the claim that TRAcP 5b could be useful as a diagnostic tool for the detection of bone metastases in patients with breast cancer.

Procollagen type 1 amino-terminal propeptide: a marker for bone metastases in prostate carcinoma.

BACKGROUND: The objective of this study was to assess the utility of the bone formation marker procollagen type 1 amino-terminal propeptide (P1NP) in indicating bone metastases in patients with prostate carcinoma. Alkaline phosphatase (AP) and prostate-specific antigen (PSA) were measured as a comparison. PATIENTS AND METHODS: The serum samples of 100 patients were analysed using a specific immunoassay. The patients were divided into three groups, 32 patients with benign prostate hyperplasia (BPH), 38 patients with prostate carcinoma and 30 patients with prostate carcinoma with bone metastases. RESULTS: PINP concentrations were elevated in about 87% of the patients with confirmed bone metastases, the P1NP levels were significantly (p < or = 0.001) higher (median: 194.7 ng/ml) than in the patients without bone involvement (median: 38.0 ng/ml) and the BPH patients (median: 42.2 ng/ml), who both presented P1NP levels within the normal range. CONCLUSION: P1NP is a reliable predictor of the presence or absence of bone metastases in prostate carcinoma.

Value of procollagen type 1 amino-terminal propeptide in patients with renal cell carcinoma.

BACKGROUND: The aim of the study was to investigate whether the bone turnover marker procollagen type 1 amino-terminal propeptide (P1NP) could be useful for the early detection of bone metastases in patients with renal cell carcinoma (RCC) and if chemotherapy influences P1NP concentrations in patients with bone metastases. PATIENTS AND METHODS: Serum samples of 36 patients were analyzed using a specific immunoassay. The patients were divided into three groups: 24 patients without metastatic spread, 6 patients with untreated bone metastases and 6 patients who had received sorafenib. RESULTS: The P1NP concentration was significantly higher (p< or =0.001) in the patients with bone metastases (median: 396.10 ng/ml) than in those without bone involvement (median: 35.53 ng/ml). The patients treated with sorafenib showed levels within the normal range (median: 28.96 ng/ml). CONCLUSION: P1NP is a significant diagnostic marker for the development of bone metastases in patients with RCC and could help to evaluate the progress of chemotherapy.

[Comparison of two methods for rapid determination of C-reactive protein with the Tina-quant].

C-reactive protein (CRP) as an acute phase protein is an important diagnostic marker for the presence and course of human processes. Out of the acute phase proteins it is one of those the concentrations increase most rapidly with its sensitivity being superior to other markers of inflammation, such as leukocytosis, erythrocytic sedimentation rate, and fever. This study compared two-point-of-care assays with the standard laboratory method Tina-quant CRP processed on a Hitachi 917: the immunofiltration assay NycoCard CRP Whole Blood and the turbidimetric immunoassay Micros CRP. Both methods are carried in the presence of a patient, by using capillary or venous blood. Seventy-eight blood samples were analyzed first in the standard laboratory routine and then by both rapid test assays. The precision of both assays was determined from the confidence interval. The results were statistically analyzed by arithmetic standard deviation mean method, variation coefficient, Spearman correlation index, Wilcoxon and Bland-Altman tests, and Passing-Bablock regression. NycoCard CRP Whole Blood showed a correlation coefficient of R = 0.9838; the precision had a coefficient of variation of CV = 1.8759% while As compared with Tina-quant CRP had R = 0.9934 and CV = 0.9160%. Both assays indicated the same results as Tina-quant CRP. Both Tina-quant CRP and NycoCard CRP Whole Blood give the best fit for the rapid determination of CRP.

Value of tumour and inflammatory markers in lung cancer.

The aim of this study was to evaluate the individual diagnostic utility of tumour and inflammatory markers in patients with different pulmonary diseases. The usefulness of neuron-specific enolase (NSE), carcino-embryonic antigen (CEA), serum pro-gastrin releasing peptide (ProGRP) and CYFRA 21-1, as tumour markers, and C-reactive protein (CRP) and tumour necrosis factor-alpha (TNFalpha) as inflammatory markers for diagnosis, treatment and monitoring of patients with different pulmonary afflictions was investigated. Eighty healthy individuals were also included. Serum samples were also obtained from 20 patients suffering from bronchitis, 20 with lung fibrosis and 30 with sarcoidosis. Moreover, serum marker levels were analyzed in 139 patients with different pulmonary malignancies: 29 patients with adenocarcinoma, 30 patients with squamous cell carcinoma, 80 patients with small cell lung cancer (SCLC). All tumour markers showed significantly elevated values in malignant diseases. The levels of ProGRP in patients with benign diseases were significantly higher than those in the healthy group (35.4 +/- 6.6 compared with 21.3 +/- 9.2 pg/ml respectively). The serum ProGRP levels were elevated in SCLC patients (1673.9 +/- 706 pg/ml). The elevation was significantly higher than that of the benign reference group. The acute phase response had a wide range in patients with malignant tumours. Serum CRP levels were significantly higher in patients with SCLC (38.5 +/- 7.6 mg/dl) than in the benign reference group. In conclusion, when serum tumour markers are abnormally elevated in patients with lung cancer, CEA, CYFRA 21-1, NSE and ProGRP are useful clinical markers, good indicators of disease extent and may have important prognostic value. In particular, NSE and ProGRP have a very high sensitivity for SCLC detection.

Saphenous vein interposition as a salvage technique for complex vascular situations during renal transplantation.

The shortage of donor organs for renal transplantation leads to the necessity of accepting organs with vascular disadvantages, such as venous difficulties (eg, shortness, disrupted vein after explantation) or arterial problems (eg, iatrogenic vascular accidents, arterial plaques, hemodynamically relevant polar arteries) and horseshoe kidneys. Consequently, such organs may not be considered for transplantation. Surgeons still have the ability to use such organs by saphenous vein interposition. This study focused on the frequency of vascular difficulties in 100 randomly selected kidney transplantations and their outcomes after arterial or venous saphenous vein interposition.

Phospholipids, tumour marker and beta-CrossLaps in diagnosis of gastric carcinoma.

INTRODUCTION: The aim of this study was to evaluate the effectiveness of the serum tumor marker levels of CEA, CA 19-9, CA 72-4 and beta-CrossLaps in gastric cancer patients. As an additional parameter, we investigated the membrane phospholipid profile of gastric cancer patients. MATERIALS AND METHODS: We measured the tumor marker and phospholipid concentrations in 40 patients suffering from gastric cancer, 12 patients suffering from pancreatitis and 40 patients with gastric ulcera. We used the Elecsys 2010 enzyme analyser to determine the concentrations of CEA, CA 19-9, CA 72-4 and beta-CrossLaps. Phospholipid fractions were determined by HPLC. RESULTS: Preoperative serum levels of CEA, CA 19-9 and CA 72-4 showed sensitivities of 47.5%, 68% and 76%, respectively. The sensitivity of beta-CrossLap was 63% for non-metastatic and 76% for metastatic gastric cancer. The phospholipid fraction of phosphatidyl ethanolamine showed elevated concentrations. CONCLUSION: Additional prognostic information can be obtained using the combined assay of these tumor markers in gastric cancer patients.

Pro-gastrin-releasing peptide (Pro-GRP), a tumor marker for small cell lung cancer.

INTRODUCTION: Gastrin-releasing peptide (Pro-GRP), a member of the bombesin family of peptides, has been shown to have mitogenic activity in small cell lung carcinoma (SCLC), and to be produced by SCLC in an autocrine fashion. We investigated the usefulness of serum pro-gastrin-releasing peptide (Pro-GRP) as a tumor marker for diagnosis, treatment and monitoring of patients with small cell lung cancer (SCLC). MATERIALS AND METHODS: This study comprised 80 healthy individuals. Serum samples were also obtained from 80 patients with small cell carcinoma, 20 with chronic bronchitis, 30 with sarcoidosis and 20 with lung fibrosis. The cut-off level of serum Pro-GRP was set at 34.2 pg/ml. RESULTS: The levels of Pro-GRP in the patients with benign diseases were significantly higher than those in the healthy group. The serum Pro-GRP levels were elevated in SCLC patients. The elevation was significantly higher than that of the benign reference group. CONCLUSION: These results show that Pro-GRP may be a potential tumor marker for small cell lung carcinoma.

Complexed PSA in routine diagnosis.

INTRODUCTION: Prostatic tumor tissue produces a more complex form of PSA (cPSA) than free PSA (fPSA). For the early detection of prostate cancer, cPSA is supposed to be more sensitive than the ratio of fPSA and tPSA. The aim of the study was to evaluate the diagnostic value of cPSA in the early detection of malignant prostatic tumor. MATERIALS AND METHODS: We evaluated the new cPSA test comparing it with the already routinely used fPSA and tPSA test. The study comprised a total of 100 patients with different urological symptoms attending the Division of Urology, University of Frankfurt, Germany. Biopsy and histological examination were performed in all cases. The histological report was compared with the laboratory results obtained by immunological and electrochemiluminescence methods. RESULTS: Forty-one had a benign tumor of the prostatic gland and 59 had a malignant process diagnosed by histological examination. The cut-off level for cPSA was at 2.3 ng/ml. Within a range of 2.0-4.0 ng/ml tPSA and a cut-off of 2.3 ng/ml for cPSA we found a tumor sensitivity of the test in 92%, proved by the histological report. cPSA allows the detection of a malignant process at an earlier stage than tPSA and even within a "normal-range" of tPSA between 2.0-4.0 ng/ml. A concentration of tPSA between 4.1 and 10 ng/ml represents a grey zone. With measurement of cPSA we achieved, in 71% of our cases, a more specific result than in obtaining the PSA ratio. We did not observe any adverse result in the concentration of cPSA concerning manipulation of the prostatic gland as seen before in the measurement of fPSA. cPSA is much more stable regarding transportation and storage. There is no loss of concentration level observed up to -20 degrees C, whereas fPSA shows a loss of 10%. CONCLUSION: We conclude that the new tumor marker cPSA is more specific in the concentration range of tPSA from 2.0-4.0 ng/ml, as well as in the grey zone between 4.0-10 ng/ml.

Diagnostic value of bone and tumour markers in patients with malignant diseases.

INTRODUCTION: Biochemical bone markers, such as the bone isoenzyme form of alkaline phosphatase, have been used to assess the bone formation phase of bone turnover in health and disease. Skeletal metastases often occur in patients with malignancies. Recent developments suggest that bone markers could be valuable clinical tools for the management of patients with metastatic bone disease. PATIENTS AND METHODS: Serum levels of BAP, along with serum levels of beta-CrossLap, were measured in a large group (n = 200) of patients with newly-diagnosed or progressive cancer of the prostate, breast, colon, liver and pancreas. Tumour markers such as PSA, CEA, CA 19-9, AFP, CA 15-3 and bone marker levels were correlated with the presence or absence of bone scan-documented metastases. RESULTS: Both of the bone markers examined were elevated in a high proportion of patients with confirmed metastases to bone. All patients with prostate, breast and colon carcinoma showed elevated beta-CrossLap values. The determined values of beta-CrossLap and BAP were significantly correlated with the number of skeletal metastases. CONCLUSION: Markers of biochemical bone remodeling can be used in assessing and managing patients with malignancies that metastasize to bone. These markers are abnormally raised in the blood of patients with metastatic bone disease.

Pre-analytical problems in the measurement of tumor type pyruvate kinase (tumor M2-PK).

INTRODUCTION: Tumor M2-PK is an isoform of the glycolytic enzyme pyruvate kinase. This isoform exists in an active tetrameric and less active dimeric form. The dimeric form is expressed by various tumor cells and can be measured in blood by a specific ELISA. MATERIALS AND METHODS: We included 500 healthy persons, 20 patients with an acute rheumatic disease (high CRP) and 30 patients with a nephropathy and proteinuria with more than 20 mg/dl. We measured Tumor M2-PK in each of these groups in different specimens of EDTA-plasma, serum, heparin-, citrate-, fluoride- and oxalate-plasma. RESULTS: We found different concentrations of Tumor M2-PK in healthy persons depending on the kind of specimen. The normal range of Tumor M2-PK concentration was higher in the serum than in the plasma, with 35 U/l compared to 15 U/l. In haemolytic material we found concentrations up to 80 U/l in healthy persons. Lipaemic or icteric serum material showed a higher concentration of Tumor M2-PK as well. In patients with a triglyceride concentration higher than 300 mg/dl, the normal range for Tumor M2-PK was measured between 30-50 U/l. Similar results were found in patients with icteric serum. Patients with an active rheumatic disease and elevated CRP concentration showed a Tumor M2-PK concentration between 40-60 U/l. Patients with a nephropathy and proteinuria over 20 mg/dl had an elevated Tumor M2-PK concentration from 25-60 U/l. CONCLUSION: We conclude that different materials seem to be suitable for the measurement of Tumor M2-PK concentration as long as attention is paid to different normal ranges. Haemolytic material should not be used as it offers false-positive results. Some diseases such as rheumatic disease, hyperlipidaemia and nephropathy have an influence on Tumor M2-PK concentration that should not be neglected.

Tumor M2-PK levels in haematological malignancies.

Circulating Tumor M2-PK serum levels were measured in 118 patients with various haematological malignancies. Using 17.5 U/ml as the cut-off level, elevated Tumor M2-PK concentrations were found in 7 out of 35 patients with acute myelocytic leukaemia, 17 out of 38 patients with chronic myelocytic leukaemia, 5 out of 18 patients with chronic lymphocytic leukaemia and in 6 out of 14 patients with acute lymphocytic leukaemia. Only 9 out of 195 healthy control individuals had Tumor M2-PK plasma levels above 17.5 U/ml. Serial determinations of Tumor M2-PK were performed in 3 patients with haematological malignancies during chemotherapy. Disease regression was associated with alternating Tumor M2-PK plasma levels. Thus, Tumor M2-PK is not a useful indicator of haematological malignancies. Moreover, serial Tumor M2-PK measurement may be insignificant in monitoring response to chemotherapy in these patients.

Pyruvate kinase type tumor M2 plasma levels in patients afflicted with rheumatic diseases.

BACKGROUND: Since tumor markers can be increased in the course of many benign diseases, the aim of this study was to verify if this also occurs in the course of rheumatic diseases. MATERIALS AND METHODS: We investigated the incidence and characteristics of Tumor M2-PK in the EDTA-plasma of 137 patients suffering from rheumatic diseases. RESULTS: The tumor M2-PK concentration was increased in 52 out of 63 patients (82%) with classical rheumatoid arthritis, in 15 out of 21 patients (71%) with systemic lupus erythematosus, in 14 out of 17 patients (82%) with seronegative spondylarthritis and in 13 out of 28 patients with miscellaneous rheumatic diseases (46%). Malignant neoplasm was not detected in any of the patients with rheumatic diseases. CONCLUSION: These results demonstrated that the EDTA-plasma concentrations of Tumor M2-PK were increased in patients with rheumatic diseases.

Tumor marker pyruvate kinase type tumor M2 in patients suffering from diabetic nephropathy.

INTRODUCTION: Compared to normal tissues all tumors investigated so far and especially those with a metastatic potential overexpress an isoenzyme of the pyruvate kinase, the pyruvate kinase type tumor M2 (TU M2-PK). Because of its monomeric structure, the TU M2-PK has no function at all. PATIENTS AND METHODS: Using an enzyme-linked immuno sorbent assay (ELISA) developed by ScheBooTech (Wettenberg, Germany) we measured the concentration of TU M2-PK in EDTA-plasma of 12 probands with insulin-dependent diabetes mellitus and 91 patients suffering from non-insulin-dependent diabetes mellitus, both with diabetic nephropathy. Moreover we focused on the way it compares to other metabolic markers such as HbA1c, glucose and proteins. RESULTS: Among the 12 patients afflicted by insulin-dependent diabetes mellitus 17%, and the 91 probands with non-insulin-dependent diabetes mellitus as many as 19% of the samples were raised over the cut-off of 25 U/ml EDTA-plasma. A correlation with the other investigated parameters could not be found. CONCLUSION: This study shows that the TU M2-PK in EDTA-plasma of patients with diabetic nephropathy presents 38.8% "false-positive" data and thus must be questioned as a tumor marker.

Value of tumor M2 (Tu M2-PK) in patients with renal carcinoma.

Pyruvate kinase is one of the glycolytic key enzymes. It exists in various isoforms which are expressed in different cell types. One of these isoforms, the type Tu M2-PK, is strongly overexpressed by tumor cells and released into body fluids. The concentration of Tu M2-PK in body fluids can be quantitatively determined by a commercially available enzyme-linked immunosorbent assay (ELISA)-kit. The Tu M2-PK concentration was measured in EDTA-plasma of 116 patients with renal carcinoma and 42 patients suffering from nephritis, by using this kit. The ranges of the Tu M2-PK-concentrations of the two groups did not overlap, indicating a highly significant discrimination of renal carcinoma and benign renal diseases. Furthermore, the Tu M2-PK concentration in EDTA-plasma correlated strongly with the Robson tumor stage of the 116 patients. The present results indicated that the Tu M2-PK might be the first tumor marker, which could be an excellent complementation of the diagnostic program for renal carcinoma.