Predictive Value of Serum Aurora A, Thymidine Kinase 1, and HER3/ErbB3 in Breast Cancer Patients Before Neoadjuvant Treatment

Further personalization is needed to improve the outcomes of breast cancer treatment. It is necessary to find new inexpensive and easily evaluated predictive markers. In this study, we determined serum level of Aurora A (AURKA), thymidine kinase 1 (TK1) and human epidermal growth factor receptor type 3 (HER3) by enzyme immunoassay ELISA. We collected peripheral blood sera of 119 women with breast cancer before neoadjuvant treatment and the control group of 47 randomly selected healthy women. After treatment we analyzed clinical data: age, initial TNM stage, tumor receptors expression: estrogen (ER), progesterone (PGR), epidermal growth factor receptor type 2 (HER2), Ki67, histological malignancy grade, biological subtype, and response to neoadjuvant treatment in residual cancer burden (RCB) classification. Pathologic complete response (PCR) was achieved in 41 patients (34.45%). In univariate analysis patients with higher AURKA levels were more likely to obtain PCR (p=0.039). In multivariate analysis we used the logit regression model with PCR as the dependent. The effect of AURKA concentration ≥4.75 ng / mL on the chance of achieving PCR was found (OR: 3.5; 95%CI: 1.2-10.1; p = 0.023). Other significant PCR factors included: node status (OR: 0.503; 95% CI: 0.263-0.965; p = 0.039), negative PGR expression (OR: 0.104; 95% CI: 0.038-0.284; p < 0.001), and Ki67 >20% (OR: 5.44; 95% CI: 1.24-23,9; p < 0.025). There was no significance in marker concentrations and clinical features nor between breast cancer patients and control group. The outcomes suggest that serum AURKA level is a potential PCR prediction marker in neoadjuvant breast cancer treatment. Further studies are needed to confirm our observations.

Thymidine Kinase 1: Making Its Mark In Immunotherapy

Cancer is one of the leading causes of death worldwide. In the U.S. alone, almost 2 million people will be diagnosed with cancer each year and just over a quarter of those diagnosed will pass away from the disease. Skin cancers are the most common forms of cancer. Early detection of cancer and cancer biomarkers enables clearer understanding of cancer progression in a patient and more effective treatments in response to the disease. Clinically relevant biomarkers are not only tools for early diagnosis of cancer but may also prove useful as immune targets for various immunotherapies, such as monoclonal antibody-based therapy and chimeric antigen receptor (CAR) T-cell therapy. This review provides a brief overview of the rescue pathway enzyme thymidine kinase 1 (TK1) and its history and biology, as well as discusses its role as a biomarker and potential immune target.

Molecular characterization of equine thymidine kinase 1 and preliminary evaluation of its suitability as a serum biomarker for equine lymphoma

Background Thymidine kinase 1 (TK1) plays a key role in the synthesis of deoxythymidine triphosphate (dTTP) and is thus important for DNA replication and cell proliferation. The expression of TK1 is highest during S-phase, and it is rapidly degraded after mitosis. In cancer cells, TK1 is upregulated, resulting in leakage of excess TK1 into the blood. Consequently, serum TK1 has been used as a diagnostic and prognostic cancer biomarker, mainly in human medicine. The aims of this work were to characterize equine TK1 and to evaluate its suitability as a serum biomarker for equine lymphoma. Results Equine TK1 was cloned, expressed in E. coli and affinity purified. The purified recombinant horse TK1 showed broad substrate specificity, phosphorylating pyrimidine deoxyribo- and ribonucleosides and, to some extent, purine deoxynucleosides, including anticancer and antiviral nucleoside analogues. ATP was the preferred phosphate donor. Serum TK1 activity was measured in samples collected from horses with confirmed or suspected lymphoma and control horses with and without concurrent diseases. Serum TK1 activity levels were significantly higher in horses with lymphoma (p < 0.0005) and suspected lymphoma (p < 0.02) and in tumour-free groups with diverse diseases (p < 0.03) than in controls without concurrent diseases. There was a significant difference between the lymphoma group and the tumour-free group with diverse diseases (p < 0.0006). Furthermore, receiver operating characteristic analysis revealed a sensitivity of 0.86, a specificity of 0.95 and an AUC (area under the curve) of 0.92 compared to the controls without concurrent diseases, with a sensitivity of 0.97, a specificity of 0.71 and an AUC of 0.88 when compared with the tumour-free group with diverse diseases. Conclusion Equine TK1 showed high specific activity and broader substrate specificity than human TK1. Anticancer and antiviral thymidine analogues were efficiently phosphorylated by horse TK1, suggesting that these analogues might be good candidates for chemotherapy in horses. Serum TK1 activity was significantly higher in horses with lymphoma than in controls. ROC analysis indicated that serum TK1 could serve as a promising cancer biomarker in horses.

Immunohistochemistry for Thymidine Kinase-1 (TK1): A Potential Tool for the Prognostic Stratification of Breast Cancer Patients

Breast cancer (BC) is the most frequent non-cutaneous malignancy in women. Histological grade, expression of estrogen and progesterone receptors (ER and PgR), overexpression/amplification of the human epidermal growth factor receptor 2 (HER2) oncogene, and proliferative activity measured with ki-67 provide important information on the biological features of BC and guide treatment choices. However, a biomarker that allows a more accurate prognostic stratification is still lacking. Thymidine kinase-1 (TK1), a ubiquitous enzyme involved in the pyrimidine nucleotide recovery pathway, is a cell-proliferation marker with potential prognostic and predictive impacts in BC. Eighty (80) cases of invasive BC with a long-term follow-up were retrospectively selected, and clinicopathological data were collected for each patient. TK1 tissue expression was evaluated immunohistochemically. Data suggested that TK1 expression levels are positively correlated with ER and PgR expression, and negatively correlated with HER2 status and the impact on patients' distant recurrence-free survival (DRFS): in detail, among patients undergoing adjuvant chemotherapy, lower TK1 levels are correlated with better DRFS. Therefore, these results contribute to furthering the knowledge of TK1, suggesting a possible and important role of this enzyme as a biomarker in the stratification of BC patients.

Dynamics of Serum Thymidine Kinase 1 at the First Cycle of Neoadjuvant Chemotherapy Predicts Outcome of Disease in Estrogen-Receptor-Positive Breast Cancer

Pathologic complete response (pCR) predicts the long-term outcome of neoadjuvantly treated (NAC) breast cancer (BC) but is reached in <10% of hormone-receptor-positive patients. Biomarkers enabling adjustment or interruption of an ineffective therapy are desired. Here, we evaluated whether changes in the serum concentration of thymidine kinase 1 (sTK1) during NAC could be utilized as a biomarker. In the PROMIX trial, women with localized HER2- BC received neoadjuvant epirubicin/docetaxel in six cycles. sTK1 was measured with an ELISA in 54 patients at cycles 1–4 and in an additional 77 patients before and 48 h after treatment 1. Treatment resulted in a 2-fold increase of sTK1 before and a 3-fold increase 48 h after the cycles, except for the first cycle, where half of the patients reacted with a significant decrease and the other half with an increase of sTK1. In Kaplan–Meier estimates of ER+ patients divided by the median of the post/pre-treatment sTK1 ratio at the first treatment cycle, OS was 97.7% and 78% (p = 0.005), and DFS was 90.7% and 68% (p = 0.006), respectively. Thus, the response of sTK1 at the first cycle of chemotherapy could be used both as an early biomarker for the guidance of chemotherapy and for the study of inherent tumor chemo-sensitivity, which could predict long-term outcome prior to therapy.

Can Serum Thymidine Kinase 1 Detect Small Invisible Malignant Tumours?

Objectives. Early detection of malignant tumour is a prerequisite for a successful treatment. Here we investigate if thymidine kinase 1 is more sensitive than imaging technology to discover small invisible malignant tumours.Material and Methods. The cellular concentration of TK1 was determined by a novel automatic chemiluminescence analyzer of magnetic particle immune sandwich minimum. The primary and secondary antibodies linked to the magnetic beads were chicken anti-human thymidine kinase 1 IgY-polyclonal antibodies (IgY pAb). The minimum number of cells able to be detected by the novel detection technology using an automatic chemiluminescence analyzer were determined based on the cellar TK1 concentration of low and high TK1 cell lines of known cell count.Results. The TK1 concentration of malignant cell was found to be 0.021 pg/cell. Assuming 200 pg of total protein/cell, TK1 corresponds to 0.01 % of the total protein/cell. The concentration of TK1 in human blood serum of malignant patients is in the range of 2-10 pmol/l (pM), corresponding to about 50 x106 growing cells in the body that release TK1 into 5 litre blood. The limit visibility by imaging of a tumour is about 1 mm in diameter, corresponding to about 109cells of a cell diameter of 1µm. Conclusion. TK1 is more sensitive than imaging.

Feline thymidine kinase 1: molecular characterization and evaluation of its serum form as a diagnostic biomarker

Background Thymidine kinase 1 (TK1) catalyzes the initial phosphorylation of thymidine in the salvage pathway synthesis of dTTP, an essential building block of DNA. TK1 is a cytosolic enzyme with its highest level during the S-phase of the cell cycle. In cancer cells TK1 is upregulated and excess TK1 is leaked into the blood. Therefore, serum TK1 has been used as biomarker for cancer diagnosis and prognosis in human medicine. Feline TK1 shows high sequence similarity to TK1 from other species. The aim of this study was to characterize feline TK1 and evaluate if serum TK1 can be used as a diagnostic biomarker. Results Feline TK1 was cloned, expressed and affinity purified. The purified feline TK1 phosphorylated not only pyrimidine deoxyribonucleosides but also pyrimidine ribonucleosides and to some extent purine deoxynucleosides. A number of anticancer and antiviral nucleoside analogs also served as substrates with fairly high efficiency. ATP and dATP were the preferred phosphate donor. Serum TK1 activity in felines with malignant diseases was significantly higher than that in healthy individuals. ROC analysis revealed an area under the curve (AUC) of 0.98 with a sensitivity of 0.83 and a specificity of 0.95 for felines with lymphoma. Serum TK1 activity in felines with IBD or inflammatory disease was within the same range as healthy ones. Furthermore, in felines with lymphoma serum TK1 activity returned to normal levels in response to treatment. Conclusion Feline TK1 has high specific activity and a broader substrate specificity in comparison with TK1 from other species. Serum TK1 activity in felines with malignant diseases is significantly higher than that in normal felines and in felines with inflammatory diseases. These results suggest that serum TK1 may be a promising biomarker for the diagnosis and monitoring of malignant diseases and for the differential diagnosis of certain inflammatory disease.

Dynamics of Serum Thymidine Kinase 1 at the First Cycle of Neoadjuvant Chemotherapy Predicts Outcome of Disease in Estrogen-receptor-positive Breast Cancer

Complete pathologic response (pCR) predicts the long-term outcome of neoadjuvant treated (NAC) breast cancer (BC) but is reached in &lt;10% of hormone-receptor-positive patients. Biomarkers able to guide adjustment or interruption of an ineffective therapy are desired. Here, we evaluated whether shifts in the serum concentration of thymidine kinase 1 (sTK1) during NAC could be utilized as a biomarker. In the PROMIX trial, women with localized HER2- BC received neoadjuvant epirubicin/docetaxel in six cycles. sTK1 was measured with an ELISA in 54 patients at cycles 1-4 and in a total of 131 patients before and 48h after cycle 1. The prognostic significance of the results was evaluated by log-rank tests of Kaplan&ndash;Meier estimates. Treatment resulted in a 2-fold increase of sTK1 before and 3-fold increase 48h after the cycles, except for the first cycle, where half of patients reacted with a decrease (post/pre sTK1- ratio &lt;1.12) and the other half reacted with an increase (ratio &gt;1.12). OS rates in ER+ patients with ratios of &gt;1.12 and &lt;1.12 were 97.7% and 78% (p=0.005), respectively, and DFS rates were 90.7% and 68% (p=0.006), respectively. Thus, response of sTK1 at the first cycle of chemotherapy could be used both as an early biomarker for guidance of chemotherapy and for the study of inherent tumor chemo-sensitivity, which could predict long-term outcome prior to therapy.