Thymidine kinase (TK1) is an enzyme involved in DNA synthesis that leaks into the blood as a result of high cell turnover, particularly in the case of cancer. Serum TK1 activity has been used for prognosis and monitoring of leukemia and lymphoma patients for many years. Here, we describe the first clinical results with the newly developed TK 210 ELISA from AroCell AB. Sera from 124 breast cancer patients with known TNM classification along with sera from 53 healthy females were analyzed by TK 210 ELISA for TK1 protein and TK1 activity levels by the 3[H]-deoxythymidine (dThd) phosphorylation assay. The limit of detection for the TK 210 ELISA was 0.17 ng/ml, and 60 % of the sera from female blood donors were below this value. The median TK1 levels found in sera from breast cancer patients with T1 to T4 stage disease were 0.31, 0.46, 0.47, and 0.55 ng/ml, and these levels significantly differed from healthy controls. The median values of the biomarker CA 15-3 were also increased in patient sera from T1 to T4 patients (16, 34, 36, 40 U/ml, respectively). TK 210 ELISA showed significantly higher sensitivity for the T1 and T2 breast cancer patients compared to the TK activity assay. The combination of the TK1 ELISA and CA 15-3 biomarkers demonstrated a significant increase in sensitivity up to 15 % compared to each marker alone. This evaluation of the TK 210 ELISA strongly suggests that it can provide independent and complementary information for patients with breast cancer.Electronic supplementary materialThe online version of this article (doi:10.1007/s13277-016-5024-z) contains supplementary material, which is available to authorized users.

Background: Autism spectrum disorder (ASD) is a developmental disorder characterized by deficits in social interaction, restricted interest and repetitive behavior. Oxidative stress in response to environmental exposure plays a role in virtually every human disease and represents a significant avenue of research into the etiology of ASD. The aim of this study was to explore the diagnostic utility of four urinary biomarkers of oxidative stress. Methods: One hundred and thirty-nine (139) children and adolescents with ASD (89% male, average age = 10.0 years, age range = 2.1 to 18.1 years) and 47 healthy children and adolescents (49% male, average age 9.2, age range = 2.5 to 20.8 years) were recruited for this study. Their urinary 8-OH-dG, 8-isoprostane, dityrosine and hexanoil-lisine were determined by using the ELISA method. Urinary creatinine was determined with the kinetic Jaffee reaction and was used to normalize all biochemical measurements. Non-parametric tests and support vector machines (SVM) with three different kernel functions (linear, radial, polynomial) were used to explore and optimize the multivariate prediction of an ASD diagnosis based on the collected biochemical measurements. The SVM models were first trained using data from a random subset of children and adolescents from the ASD group (n = 70, 90% male, average age = 9.7 years, age range = 2.1 to 17.8 years) and the control group (n = 24, 45.8% male, average age = 9.4 years, age range = 2.5 to 20.8 years) using bootstrapping, with additional synthetic minority over-sampling (SMOTE), which was utilized because of unbalanced data. The computed SVM models were then validated using the remaining data from children and adolescents from the ASD (n = 69, 88% male, average age = 10.2 years, age range = 4.3 to 18.1 years) and the control group (n = 23, 52.2% male, average age = 8.9 years, age range = 2.6 to 16.7 years). Results: Using a non-parametric test, we found a trend showing that the urinary 8-OH-dG concentration was lower in children with ASD compared to the control group (unadjusted p = 0.085). When all four biochemical measurements were combined using SVMs with a radial kernel function, we could predict an ASD diagnosis with a balanced accuracy of 73.4%, thereby accounting for an estimated 20.8% of variance (p < 0.001). The predictive accuracy expressed as the area under the curve (AUC) was solid (95% CI = 0.691–0.908). Using the validation data, we achieved significantly lower rates of classification accuracy as expressed by the balanced accuracy (60.1%), the AUC (95% CI = 0.502–0.781) and the percentage of explained variance (R2 = 3.8%). Although the radial SVMs showed less predictive power using the validation data, they do, together with ratings of standardized SVM variable importance, provide some indication that urinary levels of 8-OH-dG and 8-isoprostane are predictive of an ASD diagnosis. Conclusions: Our results indicate that the examined urinary biomarkers in combination may differentiate children with ASD from healthy peers to a significant extent. However, the etiological importance of these findings is difficult to assesses, due to the high-dimensional nature of SVMs and a radial kernel function. Nonetheless, our results show that machine learning methods may provide significant insight into ASD and other disorders that could be related to oxidative stress.

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Background: Prostate-specific antigen (PSA) is an established tumour marker for prostate cancer (PCa). Serum thymidine kinase 1 is a possible new marker for the detection of PCa.The aim of the study was to investigate the diagnostic value of the AroCell TK 210 enzyme-linked immunosorbent assay (ELISA) together with free PSA, [−2]proPSA, and Prostate Health Index (PHI) in differentiating PCa from benign urological conditions. Methods: Serum samples from 140 patients with PSA values in the range between 2 and 10 µg/L were collected at the Ljubljana University Medical Centre and the Maribor University Medical Centre. Thymidine kinase (TK1) protein levels were determined using the AroCell TK 210 ELISA and PSA-related parameters analysed with commercial assays.Results: Serum TK1 protein, total and free PSA, proPSA, PSA density (PSAD), and PHI levels in patients with confirmed PCa were significantly higher than in patients with benign urological conditions (P < 0.05). Overall, the AroCell TK 210 ELISA results showed a significant correlation with PHI (r = 0.25, P = 0.0031). Receiver-operating characteristic curve analyses were used to compare the area under the curve (AUC) of TK 210 ELISA, PHI, and PSA density. For PHI, the AUC was 0.73, comparable to those of TK 210 ELISA (0.67) and PSAD (0.66), with no significant differences in pairwise comparisons (PHI vs TK 210 ELISA P = 0.32, PHI vs PSAD P = 0.24, and TK 210 ELISA vs PSAD P = 0.95). The AUC for the combination of TK1 plus PSAD was significantly higher than those for the individual PSA-related biomarkers and marginally PHI, while the AUC for the combination of TK1 plus PHI was significantly higher than those for the individual PSA-related biomarkers except for PHI and marginally for PSAD. Total PSA concentration was the only marker, that was significantly higher in patients with an increasing Gleason grade.Conclusions: These results suggest that TK1 protein determinations together with PHI or PSAD could be a valuable additional tool in PCa management.

Oxidative stress in the follicular fluid (FF) is thought to be responsible for the abnormal development of oocytes. In our study patients with polycystic ovarian syndrome (PCOS), endometriosis, and tubal infertility factor (TIF), and healthy women with a male factor of infertility, were prospectively enrolled. From each patient, a sample of individual FF was collected from a dominant follicle. Concentration levels of TAS, 8-IP, 8-OHdG, and AMH were determined. In women with PCOS, we found significantly lower values of oxidative stress markers in the FF. 8-IP and TAS levels were lower in the FF of women with endometriosis. In women with TIF, we also found significantly lower values of all tested markers in the FF, except for 8-OHdG and AMH. We wanted to see whether the biomarker measured in the FF in an individual diagnosis could predict a successfully obtained embryo from this particular follicle. The FF 8-OHdG result in PCOS patients stood out and proved to be a good predictive marker of matured and fertilized oocytes in these patients. Further research is needed to be able to apply the acquired knowledge in improving the outcome of IVF procedures.