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Introduction: There is a growing amount of evidence showing the significant analytical bias of steroid hormone immunoassays, but large number of available immunoassays makes conduction of a single comprehensive study of this issue hardly feasible. Aim of this study was to assess the analytical bias of six heterogeneous immunoassays for serum aldosterone, cortisol, dehydroepiandrosterone sulphate (DHEAS), testosterone, 17-hydroxyprogesterone (OHP) and progesterone using the liquid chromatography coupled to the tandem mass spectrometry (LC-MS/MS). Materials and methods: This method comparison study included 49 serum samples. Testosterone, DHEAS, progesterone and cortisol immunoassays were performed on the Abbott Architect i2000SR or Alinity i analysers (Abbott Diagnostics, Chicago, USA). DiaSorin’s Liaison (DiaSorin, Saluggia, Italy) and DIAsource’s ETI-Max 3000 analysers (DIAsource ImmunoAssays, Louvain-La-Neuve, Belgium) were chosen for aldosterone and OHP immunoassay testing, respectively. All immunoassays were evaluated against the LC-MS/MS assay relying on the commercial kit (Chromsystems, Gräfelfing, Germany) and LCMS-8050 analyser (Shimadzu, Kyoto, Japan). Analytical biases were calculated and method comparison was conducted using weighted Deming regression analysis. Results: Depending on the analyte and specific immunoassay, mean relative biases ranged from -31 to + 137%. Except for the cortisol, immunoassays were positively biased. For none of the selected steroids slope and intercept 95% confidence intervals simultaneously contained 0 and 1, respectively. Conclusions: Evaluated immunoassays failed to satisfy requirements for methods’ comparability and produced significant analytical biases in respect to the LC-MS/MS assay, especially at low concentrations.

Introduction: The aim was to evaluate the BD Barricor tubes by comparison with the BD Rapid Serum Tubes (RST) through measuring 25 analytes and monitoring sample stability after 24 hours and 7 days. Materials and methods: Samples of 52 patients from different hospital departments were examined. Blood was collected in BD RST and BD Barricor tubes (Becton, Dickinson and Company, Franklin Lakes, USA). Analytes were measured by Beckman Coulter AU 480 (Beckman Coulter, Brea, USA), Dimension EXL (Siemens Healthcare Diagnostics, Newark, USA) and ARCHITECT i2000SR (Abbott Diagnostics, Lake Forest, USA). Between-tube comparison for each analyte was performed, along with testing analyte stability after storing samples at 4 °C. Results: BD Barricor tubes showed unacceptable bias compared to BD RST tubes for potassium (K) (- 4.5%) and total protein (4.4%). Analyte stability after 24 hours was acceptable in both tested tubes for most of analytes, except for glucose, aspartate aminotransferase (AST) and lactate dehydrogenase (LD) in BD Barricor and free triiodothyronine in BD RST sample tubes. Analyte stability after 7 days was unacceptable for sodium, K, calcium, creatine kinase isoenzyme MB, AST, LD and troponin I in both samples; additionally for glucose, alkaline phosphatase and albumin in BD Barricor. Conclusion: All analytes, except K and total protein, can be measured interchangeably in BD RST and BD Barricor tubes, applying the same reference intervals. For most of the analytes, sample re-analysis can be performed in both tubes after 24 hours and 7 days, although BD RST tubes show better 7-day analytes stability over BD Barricor tubes.

Background: Carbohydrate sulfotransferases (CHST) were shown to be involved in carcinogenesis. The aim of the study was to assess the diagnostic value of serum CHST7 concentration in differentiation between lung cancer and non-malignant pulmonary inflammations. Methods: Clinical case-control study involving 125 participants was conducted: the control group containing cases of pneumonia and chronic obstructive pulmonary disease was compared to the lung cancer group composed of primary and metastatic cancers. Serum concentrations of CHST7 and routinely used markers including carcinoembryonic antigen (CEA), cytokeratin fragment 21-1 (CYFRA 21-1) and neuron-specific enolase (NSE) were determined for each participant using immunochemical methods. Statistical association, receiver operating characteristic (ROC) analysis and cross-validation were used for the evaluation of CHST7 either as a standalone biomarker or as a part of a biomarker panel. Results: In comparison to the control group, serum CHST7 was elevated in lung cancer (p Conclusions: Serum CHST7 is a promising biomarker for the differentiation between lung cancer and non-malignant pulmonary inflammations.

The objective was to determine the impact of VKORC1 polymorphisms on warfarin anticoagulant therapy (stable warfarin maintenance dose, time required to reach therapeutic dose and time spent in therapeutic range) and its adverse events (overanticoagulation and bleeding events, time to first overanticoagulation or bleeding event, and therapy for bleeding events) in Croatian patients. Blood samples were collected from 186 patients on stable warfarin therapy. VKORC1 1173C>T and VKORC1 – 1639G>A gene polymorphisms were analyzed using real-time PCR. Prothrombin time international normalized ratio (INR) values were determined and overanticoagulation as well as bleeding events were recorded. Both tested VKORC1 gene polymorphisms (VKORC1 1173C>T and VKORC1 –1639G>A) were in perfect linkage disequilibrium. Genotype analysis showed that 33.9% of patients were homozygous for wild- type, 46.8% were heterozygous and 19.4% were homozygous for the variant allele. We have found a statistically significant difference between variantallele carriers and wild-type patients in stable warfarin maintenance dose (p < 0.001) and incidence of bleeding events (p = 0.040). Patients homozygous for variant-allele were more likely to experience an overanticoagulation event in the first 30 days of therapy (p = 0.040). Our study showed that VKORC1 1173C>T and VKORC1 –1639G>A gene polymorphisms are associated with stable warfarin maintenance dose and adverse events of warfarin therapy.

In this study, we present a case of falsely elevated oestradiol (E2) concentration, determined by two immunoassays, in a breast cancer patient receiving exemestane therapy. The positive bias of immunochemical measurements was revealed using liquid chromatography tandem mass spectrometry which showed undetectable E2 concentration. The discrepancy is expected to be a consequence of the structural resemblance of E2 and exemestane sharing the same steroidal backbone. Inaccurate laboratory findings in therapy monitoring, as in this case, may lead to unnecessary changes of therapy.

Single nucleotide polymorphisms (SNPs) in the promotor regions of cytokine genes included in angiogenesis may influence prostate cancer (PCa) development via regulation of the pathways of tumor angiogenesis. The aim of the present study was to investigate the association of IL-1 female +3954 (rs1143634) and IL-10-1082 (rs1800896) polymorphisms with PCa risk and aggressiveness in eastern Croatian patients. One hundred twenty PCa patients and 120 benign prostatic hyperplasia (BPH) controls were genotyped using real-time PCR (LightCycler Instrument, Roche Diagnostics) and the melting curve analysis method. There was no significant difference in the frequency of genotypes for the two polymorphisms between PCa patients and controls (Χ2 = 0.857, p = 0.355 for IL-female 1; Χ2 = 0.026, p = 0.872 for IL-10). Carriers of the IL-10-1082AG variant were found to be associated with the Gleason score (GS)7 (AA versus GA+GG, OR = 3.47, 95% CI 1.11-10.88, p = 0.033). There was no significant difference in the frequency of genotypes for the two polymorphisms and the presence of metastatic disease in PCa patients. These results suggest that tested SNPs associated with differential production of IL-1 female and IL-10 are not risk factors for PCa and do not correlate with the presence of distant metastasis in eastern Croatians. We found that IL-10-1082 GA+/or GG carriers have a higher risk of developing PCa with GS7 in eastern Croatians.

Vitamin K epoxide reductase (VKOR) is a key enzyme in the y-carboxylation of proteins associated with important bodily functions (coagulation, bone metabolism, etc.). This feature is particularly used in warfarin therapy, which blocks the VKOR enzyme and leads to production of dysfunctional coagulation proteins. Genetic factors, particularly vitamin K epoxide reductase complex 1 (VKORC1) gene, have greatest influence on warfarin therapy. The aim of this study was to determine the distribution of VKORC1 1173CT and VKORC1 -1639GA polymorphisms, which are most important for warfarin therapy. We investigated 420 unrelated healthy individuals, mostly blood donors, from region of the Eastern Croatia. Both investigated polymorphisms were in perfect linkage disequilibrium (LD) and showed identical results. 151 patients (36%) were homozygous for the wild-type (C/C and G/G), 196 (47%) were heterozygous (C/T and G/A) and 73 (17%) were homozygous for the variant allele (T/T and A/A). Number of normal alleles among individuals was 498 (59.3%), and number of variant alleles was 342 (40.7%). The data obtained are in good agreement with the results of studies in other European populations.

Cytochrome P450 1A1 (CYP1A1) is an enzyme participating in the bioactivation of various endogenous and environmental reactive compounds that can bind to DNA and thus induce cancerogenesis. Gene encoding the enzyme is expressed in the prostate tissue and is polymorphic. CYP1A1*2A gene polymorphism is associated with elevated enzyme activity and/or inducibility which can lead to accumulation of genotoxic compounds and consequently to cancerogenesis. We examined the association of this polymorphism with prostate cancer (PCa) risk and aggressiveness. The case-control study consisted of 120 PCa patients and 120 benign prostatic hyperplasia (BPH) controls, in Croatian population. Regarding aggressiveness, PCa patients were grouped according to the Gleason score (GS), tumor stage (T) and existence of distant metastasis (M). The polymorphism was analyzed using real-time polymerase chain reaction (PCR). We did not observe association of mutated allele with PCa risk, neither with PCa aggressiveness. Furthermore, frequency of polymorphic genotype was slightly higher in BPH group (16.6% vs. 14.2%, respectively) and also in less aggressive form of PCa (20.4% vs. 9.6% for GS

Diagnostic value of available tumor markers, such as cancer antigen CA 15-3 and carcinoembryonic antigen (CEA) in breast cancer is limited. There is an ongoing search for additional, potentially better diagnostic blood markers with improved clinical utility. The aim of this study is to evaluate performance of the approach based on routine blood tests accompanied by a statistical learning tool to the diagnosis of breast cancer.Blood was collected from total of 104 subjects which were divided into two groups: breast cancer patients and a control group that consisted of asymptomatic volunteers and patients who had benign breast lesions at the time of blood collection. Random forest statistical learning method and the external method validation have been applied to evaluate diagnostic performance of 31 routine blood tests.The applied statistical learning approach assigned the highest diagnostic importance to the anemia panel among all analyzed blood tests that also included CA 15-3. External validation has shown utility of selected statistical approach – we were able to select tests that provide a diagnostic accuracy comparable to some diagnostic tools described in literature and based on more demanding laboratory techniques, such as gene expression microarrays.Inclusion of tests for anemia significantly improves diagnostic accuracy for the breast cancer in comparison to the diagnostic accuracy of the CA 15-3 alone. Application of the random forests also enables the reduction of number of laboratory tests needed for the establishment of diagnosis. Differences in relevant test values between the cancer and control group are small but application of multiparametric statistical learning ensured diagnostic accuracy of 72.0% associated by a sensitivity of 64.7% and specificity of 84.9%.