Thymidine Kinase-1 as Additional Diagnostic Marker of Prostate Cancer

BACKGROUND

Thymidine kinase-1 (TK-1) is associated with proliferation and malignancy and has been extensively studied as a diagnostic biomarker for a variety of tumors, but there are limited data for prostate cancer.

METHODS

TK-1 concentrations in serum were measured in 59 patients with prostate cancer (mean age 68 years) and in the control group of 28 healthy men (mean age 63 years) using commercially available enzymatic immunoassay (LSBio, Inc., Seattle, WA, USA). The patients were divided with respect to the severity of the disease into two groups according to the European Association of Urology (EAU) guidelines (Stage 1, 2 - less severe tumors, stage 3 - severe tumors).

RESULTS

Serum thymidine kinase-1 concentrations were significantly elevated in the group of the patients with prostate cancer compared to the healthy individuals (0.204 pmol/L vs. 0.072 pmol/L, with p < 0.0001). Diagnostic efficiency of serum TK-1 concentrations was 0.792 with the specificity of 53.6% and sensitivity of 94.9%. Patients with less severe tumors (Stage 1, 2) and severe tumors (Stage 3) had significantly increased levels of TK-1 as well (p < 0.0001). Combination of TK-1 and PSA investigation in patients with PCa improve the diagnostic validity of TK-1 (AUC = 0.87).

CONCLUSIONS

Concentrations of thymidine kinase 1 are increased in all patients with prostate cancer and even more in patients with severe prostate cancer. Thymidine kinase 1 appears to be a promising additional diagnostic marker promising in patients with prostate cancer.

Plasma Thymidine Kinase Activity as a Biomarker in Patients with Luminal Metastatic Breast Cancer Treated with Palbociclib within the TREnd Trial

PURPOSE

Thymidine kinase 1 (TK1) is downstream to the CDK4/6 pathway, and TK activity (TKa) measured in blood is a dynamic marker of outcome in patients with advanced breast cancer (ABC). This study explores TK1 as a biomarker of palbociclib response, both in vitro and in patients with ABC.

EXPERIMENTAL DESIGN

Modulation of TK1 levels and activity by palbociclib were studied in seven estrogen receptor-positive breast cancer cell lines: sensitive (PDS) and with palbociclib acquired resistance (PDR). TKa was assayed in plasma obtained at baseline (T0), after one cycle (T1), and at disease progression on palbociclib (T2) in patients enrolled in the "To Reverse ENDocrine Resistance" (TREnd) trial (n = 46).

RESULTS

Among E2F-dependent genes, TK1 was significantly downregulated after short-term palbociclib. Early TKa reduction by palbociclib occurred in PDS but not in PDR cells. In patients, median TKa (mTKa) at T0 was 75 DiviTum units per liter (Du/L), with baseline TKa not proving prognostic. At T1, mTKa decreased to 35 Du/L, with a minority of patients (n = 8) showing an increase-correlating with a worse outcome than those with decreased/stable TKa (n = 33; mPFS 3.0 vs 9.0 months; P = 0.002). At T2, mTKa was 251 Du/L; patients with TKa above the median had worse outcomes on post-study treatment compared with those with lower TKa (2.9 vs 8.7 months; P = 0.05).

CONCLUSIONS

TK is a dynamic marker of resistance to palbociclib which may lead to early identification of patients in whom treatment escalation may be feasible. In addition, TKa may stratify prognosis in patients with acquired resistance to palbociclib.

The combination of AroCell TK 210 ELISA with Prostate Health Index or prostate-specific antigen density can improve the ability to differentiate prostate cancer from noncancerous conditions

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.

Serum Thymidine Kinase and Beta-2 Microglobulin in Monoclonal Gammopathies

We evaluated the serum thymidine kinase (TK) and β-2 microglobulin (β-2) levels of 22 patients with monoclonal gammopathy of undetermined significance (MGUS) and of 29 patients with multiple myeloma (MM). Both parameters were significantly lower in MGUS than in MM patients and in early (stage I+II) than in advanced (stage III) MM. TK was also lower in MGUS than in stage I MM (p < 0.025). A seven-fold increase of TK level was documented in one patient who developed a full blown picture of MM 6 years after a diagnosis of MGUS. In 3 patients with stage III MM, a sharp decrease in TK (40–77%) and in β-2 (29–53%) levels at remission was evident with respect to the levels measured at diagnosis. Patients with high levels of TK or [3-2 had a shorter survival than those with low levels; however, this was statistically significant only for β-2 levels (p < 0.02). Serum TK as well as β-2 levels appear to be of clinical value in monoclonal gammopathies and related to the course of the disease.

Serum Thymidine Kinase (TK) Evaluation in HIV Infection

Serum thymidine kinase (TK), measured using Prolifigen TK-REA, from AB Sangtec Medical, was investigated in 24 HIV seropositive patients without immunological alterations, 26 seropositives with immunological alterations, 125 LAS, 25 ARC, and 20 AIDS. Subjects with serological markers of prior EBV, HBV, and CMV infection were included but none with acute infectious mononucleosis or acute viral hepatitis. Serum TK was elevated from the beginning of the HIV infection, the seropositive stage, and more markedly afterwards during the course of the infection, with a close correlation with the stage.

TK also increased during AZT treatment, due to bone-marrow toxicity. On lowering the dosage or discontinuing the drug TK returned to basal levels.

Although the rise in serum may well not be correlated only with the HIV infection, it does add to the picture given by other clinical and/or laboratory methods. Serum TK can be a helpful laboratory test in the follow-up ofpatients with HIV infection, especially when serum levels are disproportionate to the stage, opportunistic infections, lymphoproliferative malignancies. In such cases bone-marrow toxicity due to treatment can be suspected.

Correlation of Biochemical Tumor Markers with Conventional Pathological Features in Primary Breast Cancer

In this prospective study the correlation of pathological with biological prognostic factors and serum tumor markers has been investigated in 574 patients with primary invasive breast cancer. The p53 protein and Bax level correlated positively with tumor size, lymph node status and histological grade. The serum levels of CEA, CA 15.3, TPA-M and TK correlated with tumor extent. There was a significant difference between pre- and postmenopausal breast cancer patients in serum levels of TPA-M and cytosol levels of Bax. Whether these correlations can help in predicting the prognosis of breast cancer by providing additional information with respect to the conventional factors, will have to be investigated by several years of careful clinical follow-up.

The Clinical Significance of Thymidine Kinase 1 Measurement in Serum of Breast Cancer Patients Using Anti-TK1 Antibody

The activity of total thymidine kinase in serum (S-TK) has been used as a tumor maker for decades. To date such activity has been determined using [125]I-iodo-deoxyuridine as a substrate. The aim of this study was to develop a new, antibody-based technique for the measurement of cytoplasmic thymidine kinase (TK1) in serum. Both mono- and polyclonal antibodies against S-TK1 were used in dot blot assay. S-TK1 was characterized by SDS and IEF techniques. Sixty-five breast cancer patients were studied, including 17 preoperative and 38 postoperative tumor-free patients and 10 patients with metastases to the lymph nodes (N1–2). They were compared to patients with benign tumors (n=21) and healthy volunteers (n=11). S-TK1 was low (0–1.0 pM) in healthy volunteers, while in preoperative patients the level was increased 6–110-fold. Significant differences were observed between preoperative patients and healthy volunteers (p=0.005), preoperative patients and patients with benign tumors (p<0.001), and preoperative patients and postoperative patients without metastases (p<0.001). No significant difference was observed between preoperative patients and postoperative patients with metastases (p=0.191). The S-TK activity in preoperative patients was also high in serum, but no decrease was observed following surgery. In conclusion, the anti-TK1 antibody could be a good marker for monitoring the response of breast cancer patients to therapy.

The Half-Life of Thymidine Kinase 1 in Serum Measured by ECL Dot Blot: A Potential Marker for Monitoring the Response to Surgery of Patients with Gastric Cancer

Thymidine kinase 1 in serum (STK1) of patients with gastric cancer was determined by two methods: ECL dot blot and radioactivity assay. Both measurements showed significantly different values for preoperative STK1 and healthy STK1 (p=0.012 for ECL dot blot and p=0.003 for the radioactivity assay). The preliminary results of ECL dot blot STK1 measurement showed that in tumor-free subjects the level of the enzyme was significantly reduced to 52.7% 35 days after surgery (n=8, p=0.0106). The decrease in STK1 levels in the tumor-free subjects paralleled the decline of the half-life of the STK1 enzyme. In patients with distant metastases (n=6) the enzyme level had increased to 173% 35 days postoperatively. By contrast, with the radioactivity assay no significant differences in thymidine kinase activity for 0-day-postoperative patients and 35-day-postoperative tumor-free patients was found (p=0.329). The activity decreased to 80% in 35-day-postoperative patients with metastatic disease. We suggest that the value of the half-life of STK1 measured by ECL dot blot can be used as a potential marker for monitoring the response to surgery in patients with gastric or other cancers one month after surgery.

Research on application value of combined detection of serum CA125, HE4 and TK1 in the diagnosis of ovarian cancer

OBJECTIVE

To explore the diagnostic value of joint examination of cancer antigen 125 (CA125), thymidine kinase-1 (TK1) and human epididymis protein 4 (HE4) in the serum of patients with ovarian cancer.

PATIENTS AND METHODS

A total of 75 ovarian cancer specimens (ovarian cancer group), 40 benign ovarian specimens (benign group) and 35 ovarian specimens of healthy women (normal control group) were collected. The serum levels of HE4, CA125 and TK1 and the positive detection rates in the three groups were compared. Meanwhile, the sensitivity and specificity of the three tumor markers in the diagnosis of ovarian cancer in the three groups were compared.

RESULTS

The levels of HE4, CA125 and TK1 in the ovarian cancer group were significantly higher than those in the control group (p<0.05), and those in the ovarian cancer group were significantly higher than those in the benign group (p<0.05). The positive rates of CA125 as well as TK1 in the ovarian cancer group and the benign group were significantly higher than those in the control group (p<0.05), and those in the ovarian cancer group were significantly higher than those in the benign group (p<0.05). In the detection of an individual tumor marker, the sensitivity of CA125 was the highest, followed by HE4. The specificity of HE4 was the highest, followed by TK1. For the combination of two tumor markers, the sensitivity of CA125+HE4 ranked the first (92.18%), and the specificity of TK1+HE4 ranked the first (88.37%). The sensitivity and specificity of the joint detection of CA125+HE4+TK1 were 94.18% and 79.53%, respectively. The sensitivity of the joint detection of CA125+HE4+TK1 was significantly higher than that of the detection of a single tumor marker and that of joint detection of two tumor markers (p<0.05).

CONCLUSIONS

Combined detection of CA125, HE4 and TK1 can significantly improve the sensitivity in the diagnosis of ovarian cancer.

Serum Thymidine Kinase 1 Activity Following Nephrectomy for Renal Cell Carcinoma and Radiofrequency Ablation of Metastases to Lung and Liver

BACKGROUND/AIM

Thymidine kinase 1 (TK1) is involved in DNA synthesis and is considered a reliable and sensitive marker of cell proliferation. The aim of this study was to investigate the prognostic value of measurements of serum TK1 activity following tumor ablation.

PATIENTS AND METHODS

This study was performed on 32 patients with renal cell carcinoma (RCC) who had undergone nephrectomy and 35 patients with cancer of different histology with metastases to the liver (n=28) and lung (n=7) treated with radiofrequency ablation (RFA). The TK1 activity was measured with DiviTum (Biovica) immunoassay.

RESULTS

In patients with RCC with no evidence of disease during their observation, a significant decrease of the TK1 activity was observed on the day following nephrectomy (p<0.0001). The mean calculated half-life ±SEM was 10.8±1.2 h. Taking into account the short half-life, measurements of TK1 were performed 24 h after nephrectomy or RFA of metastases. It was found that elevated TK1 activity (>60 Du/l) on the day after nephrectomy independently predicted poor recurrence-free survival (hazard ratio=5.0, p=0.040), after adjustment for T-stage, age and pretreatment TK1. Patients scheduled for RFA averaged 1.4 lesions and an average lesion diameter of 2.2 cm. Multivariate Cox's regression model demonstrated the significant association of any increase of TK1 activity or decrease not reaching ≤60 Du/l on the day after ablation with poor progression-free survival (hazard ratio=4.6, p=0.001), after adjustment for the type of primary tumor, the number and size of metastases.

CONCLUSION

The half-life for serum TK1 activity is 10.8±1.2 h. The measurements of TK1 activity following nephrectomy or RFA of metastases could be an important tool in prognostic evaluation.

A New Sandwich ELISA for Quantification of Thymidine Kinase 1 Protein Levels in Sera from Dogs with Different Malignancies Can Aid in Disease Management

Thymidine kinase 1 (TK1) is a DNA precursor enzyme whose expression is closely correlated with cell proliferation and cell turnover. Sensitive serum TK1 activity assays have been used for monitoring and prognosis of hematological malignancies in both humans and dogs. Here we describe the development of a specific sandwich TK1-ELISA for the quantification of TK1 protein levels in sera from dogs with different malignancies. A combination of rabbit polyclonal anti-dog TK1 antibody and a mouse monoclonal anti-human TK1 antibody was used. Different concentrations of recombinant canine TK1 was used as standard. Clinical evaluation of the ELISA was done by using sera from 42 healthy dogs, 43 dogs with hematological tumors and 55 with solid tumors. An established [³H]-dThd phosphorylation assay was used to determine the TK1 activity levels in the same sera. The mean TK1 activities in dogs with hematological tumors were significantly higher than those found in healthy dogs. In agreement with earlier studies, no significant difference was observed in serum TK1 activities between healthy dogs and dogs with solid tumors. However, the mean TK1 protein levels determined by new TK1-ELISA were significantly higher not only in hematological tumors but also in solid tumors compared to healthy dogs (mean ± SD = 1.30 ± 1.16, 0.67 ± 0.55 and 0.27± 0.10 ng/mL, respectively). Moreover, TK1-ELISA had significantly higher ability to distinguish lymphoma cases from healthy based on receiver operating characteristic analyses (area under the curve, AUC, of 0.96) to that of the activity assay (AUC, 0.84). Furthermore, fluctuations in TK1 protein levels during the course of chemotherapy in dogs with lymphoma closely associated with clinical outcome. Overall, the TK1-ELISA showed significant linear correlation with the TK1 activity assay (r_s = 0.6, p<0.0001). Thus, the new TK1-ELISA has sufficient sensitivity and specificity for routine clinical use in veterinary oncology.

Thymidine kinase levels correlate with prognosis in aggressive lymphoma and can discriminate patients with a clinical suspicion of indolent to aggressive transformation

Serum levels of thymidine kinase 1 (TK1), an enzyme involved in the G1-S phase of the cell cycle, have been previously shown to correlate with the prognosis of lymphoid malignancies. We hypothesized that TK1 levels will be higher in aggressive, compared to indolent lymphoproliferative, malignancies and this may serve as a marker of transformation from an indolent to aggressive disease. We analyzed serum from 182 patients and correlated the findings with the type of malignancy and prognosis; we further compared the TK1 levels of 31 patients with a proven transformation and 34 patients with clinically suspected transformation that was eventually deferred. The mean TK1 levels of patients with indolent and aggressive disease was 18.9±3.3 and 39.8±3.3 U/l respectively (p<0.001). Among patients with aggressive disease, low TK1 levels correlated with improved survival (p=0.008). TK1 levels >16.6 U/l predicted transformation from indolent to aggressive disease (sensitivity of 95%, specificity of 76%, negative predictive value (NPV) of 96% and positive predictive value (PPV) of 69%). A regression analysis showed that only TK1 levels were significant (relative risk (RR)=1.03 for each unit, confidence interval (CI)=1-1.05; p=0.015) for diagnosing a true transformation. In conclusion, TK levels are useful in assessing prognosis, especially in aggressive lymphoproliferative diseases. Moreover, TK levels are adequate in discriminating cases of indolent lymphoma that transformed to an aggressive disease from patients with no proven transformations. This tool provides the clinician a novel method to distinguish between symptomatic patients utilizing a simple test and may lessen the need for aggressive or invasive measures of investigation.

Serum detection of thymidine kinase 1 as a means of early detection of lung cancer

BACKGROUND

Thymidine kinase 1 (TK1) is a biomarker elevated in several malignancies, including lung cancer. Up-regulation of TK1 is an early event in carcinogenesis and therefore a target for early cancer detection. We have developed a novel Enzyme Linked Immunosorbent Assay (ELISA) to detect TK1 in serum.

MATERIALS AND METHODS

Forty patients with pulmonary nodules and 18 healthy individuals had their serum collected prior to surgery. All samples were analyzed using a radioassay and ELISA.

RESULTS

TK1 was significantly elevated in all lung cancer samples. Patients with stage I (n=16) and stage II (n=17) disease had significantly higher TK1 levels than controls. The area under the curve was 0.792, using 4.9 nM TK1 as cut-off, for early-stage lung cancer. The sensitivity and specificity were 75.0 and 83.3, respectively. TK1 concentration was a more sensitive and accurate indicator of lung cancer than TK1 activity.

CONCLUSION

TK1 is significantly elevated in serum from patients with stage I and stage II lung cancer as measured using the established ELISA. This novel TK1 ELISA is both sensitive and specific for the detection of early-stage and advanced lung cancer, and therefore may be an important tool in the management of this disease.

Serum thymidine kinase activity: analytical performance, age-related reference ranges and validation in chronic lymphocytic leukemia

Background

To date no age-related reference ranges are available for serum thymidine kinase (TK1) activity. Being a proliferation marker, it may be used as a prognostic marker in malignant diseases, including chronic lymphocytic leukemia (CLL). Our aim was to establish age-specific reference ranges for TK1 and examine its utility as a screening marker in CLL, a disease of the elderly.

Methods

Serum TK1 activity was measured by a competitive chemiluminescent immunoassay in 369 healthy adults and 115 de novo CLL patients.

Results

We observed a statistically significant decline in TK1 activity from young (18–35 years) to middle-aged (36–60 years) and further on to elderly (60–86 years) healthy individuals. Age-related reference range was: <30 U/L for young, <25 U/L for middle-aged and <19 U/L for elderly. There was no difference in TK1 activity between the studied healthy men and women. In CLL patients, TK1 activity was the highest in the advanced Rai stages. The area under the receiver operating characteristic curve (ROC-AUC) for TK1 was 0.840 (95% CI: 0.787–0.892), for differentiating CLL patients from age and sex matched healthy controls, with a cut-off value of 10.5 U/L (sensitivity: 80.9%, specificity: 73.4%). TK1 was significantly elevated in CD38+/Zap70+ CLL patients, and showed significant correlation with WBC and absolute B-cell count.

Conclusion

In the healthy, serum TK1 activity does not differ in the two sexes but declines significantly with age. As such, use of age-related reference ranges is warranted, especially when evaluating CLL patients who generally belong to the elderly age group.

[Blood test for malignant lymphoma]

Malignant lymphoma is a neoplastic disease that develops in the lymph system, which consists of various different subtypes. In addition, the differential diagnosis of malignant lymphoma includes infections, autoimmune diseases, allergic diseases, endocrine disorders, and so on. Therefore accurate diagnosis is very important to decide therapeutic strategy. Blood test is the most common examination in clinical practice and used extensively for evaluating etiology, pathology, disease state, efficacy of treatment and disease prognosis of lymphoma. We are required to understand the characteristics of blood examinations correctly and use them appropriately in daily medical practice. Here, we introduce some blood examinations used for treatment of lymphoma.

[Analysis of correlation between serum thymidine kinase 1 and acute myeloid leukemia]

This study was purposed to investigate the clinical significance of serum thymidine kinase 1 (STK1) level change in acute myeloid leukemia (AML). Peripheral blood samples of 60 newly diagnosed AML patients were collected and the STK1 levels were determined by enhanced chemiluminescent dot-blot method before and at two weeks after start of inductive treatment and in consolidatory treatment. Using non-parametric test, the differences between groups were analyzed. Then the correlation between STK1 level and clinical characteristics was explored by a way of chi-square test. The results indicated that the serum TK1 level in complete remission (CR) or partial remission (PR) AML patients decreased in varying degree as compared to pretreatment (P < 0.05), while there was no significant difference of TK1 level in non-remission (NR) ones (P > 0.05). The serum TK1 level in CR patients remained low level but increased noticeably after relapse into progressive disease (P < 0.05). A significant correlation was found between STK1 level and chromosomal abnormalities, serum LDH level as well as whether had fever in de novo AML patients (P < 0.05). It is concluded that the serum TK1 level change may be applied for reflecting the aggressiveness of disease, monitoring the clinical response to chemotherapy, evaluating the prognosis and predicating the relapse risk. The decrease of TK1 level suggests effective treatment and tumor burden reduction, while its increase indicate poor prognosis and relapse risk.

Activity of thymidilate "salvage pathway" enzymes in human gastric cancer and blood serum: correlation with treatment modalities

A comparative study of enzyme activity features of thymidilate "salvage pathway" synthesis in blood serum and tissues of different age patients with gastric cancer (T(3-4)N(0-x)M(0)) was carried out.

AIM

To evaluate the diagnostic relevance of thymidilate metabolism enzymes activities and their association with tumor growth.

METHODS

Enzymes activities were determined by the radioisotope method and spectrophotometrically in tumor tissues and blood serum of 74 patients.

RESULTS

It was demonstrated that thymidine phosphorylase activity in gastric tumors is lower by 2.6 times as compared to non-neoplastic mucosa of resection margin. This being accompanied by decrease of its activity in the blood serum (from 47.9 ± 2.6 to 14.65 ± 2.4 nmol/min·mg, p < 0.001). An increase of thymidine kinase activity was revealed both in tumor tissues (more than 3.5 times) and in blood serum (from 3.9 ± 0,7 nmol/mg·h, to 6.8 ± 1.0 nmol/mg·h, p < 0.01). Changes in their activity in the postoperative period depended on the type of surgical procedure and tumor eradication.

CONCLUSION

It could be suggested that control of individual dynamics of the enzymes activities in blood serum may be used as informative tool for monitoring of patients and treatment optimization.

Identifying the stage of new CLL patients using TK, ZAP-70, CD38 levels

Serum thymidine kinase (TK), zeta-associated protein of 70 kDa (ZAP-70) and CD38 levels have been shown to be correlated with survival in chronic lymphocytic leukaemia (CLL).

AIM

To investigate the possible correlations between TK, ZAP-70 and CD38 levels as prognostic markers in new diagnosed Rai stages of CLL patients.

METHODS

120 CLL patients were enrolled. ELISA was used to measure serum TK level, flow cytomerty - to determine ZAP-70 and CD38 expression applying ZAP-70 Kit and monoclonal antibody to CD38, respectively.

RESULTS

Significantly higher levels of TK were found in the high progression group of CLL patients that corresponded to stage II (Rai classification). An elevated level of TK, CD38 and ZAP-70 together was also found in the II stage. The coefficient of correlation between CD38 and ZAP-70 is reliable (p < 0.001). There is also a correlation between the level of TK and the disease stage (p < 0.05). Other parameters do not show this correlation.

CONCLUSION

The determination of TK, ZAP-70 and CD38 together allows patients susceptible to a possible stage of the disease, to be identified. Estimation of the factors at an early stage of the disease may allow an earlier commencement of treatment.

[Can tumor markers predict outcomes of portal vein branch embolization in patients with primary inoperable liver tumors?]

INTRODUCTION

Portal vein embolization (PVE) is one of the options to increase the number of resecable cases in patients with primary inoperable liver tumors. However, insufficient growth of liver parenchyma or postoperative tumor progression remains problematic in PVE procedures. Generally, tumor markers are of significance in patient postoperative monitoring for the disease recurrence. The aim of this study is to assess the potential of tumor markers in predicting PVE outcomes.

METHOD

The study group included 43 subjects with primary or secondary tumors, in whom serum alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), thymidine kinase (TK), tissue polypetide antigen (TPS) and MonoTotal levels were assessed 28 days following PVE. The liver parenchyma growth or tumor progression were assessed based on computer tomography.

RESULTS

Sufficient liver parenchyma hypertrophy was recorded in 27 (62.8 %) patients with subsequent liver resection. Insufficient post-PVE liver parenchyma growth was recorded in 5 (11.6 %) patients and tumor progression was recorded in 11 (25.6 %) subjects. The following tests were considered significant predictive tumor markers of PVE outcomes: serum levels of CEA, TPA, Mono Total prior to PVE, and serum levels of TK, TPA, Mono Total within 28 days following PVE.

CONCLUSION

Tumor markers may be significant in predicting PVE outcomes in patients with primary inoperable liver tumors. However, in order to make final conclusions on their clinical significance, larger patient group studies should be performed.

Evaluation of tumour markers as differential diagnostic tool in patients with suspicion of liver metastases from breast cancer

AIM

The liver is the site of breast cancer metastasis in 50% of patients with advanced disease. Tumour markers have been demonstrated as being useful in follow-up of patients with breast cancer, in early detection of recurrence of breast cancer after radical surgical treatments, and in assessing oncologic therapy effect, but no study has been carried out on their usefullness in distinguishing benign liver lesions from breast cancer metastases. The aim of this study was therefore to evaluate the importance of tumour markers carcinoembryonic antigen (CEA), carbohydrate antigen CA19-9 (CA19-9), thymidine kinase (TK), tissue polypeptide antigen (TPA), tissue polypeptide-specific antigen (TPS) and cytokeratin 19 fragment (CYFRA 21-1) in differential diagnosis between benign liver lesions and liver metastases of breast cancer.

PATIENTS AND METHODS

The study includes 3 groups: 22 patients with liver metastases of breast cancer; 39 patients with benign liver lesions (hemangioma, focal nodular hyperplasia, liver cyst, hepatocellular adenoma); and 21 patients without any liver disease or lesion that were operated on for benign extrahepatic diseases (groin hernia, varices of lower limbs) as a control group. The serum levels of tumour markers were assessed by means of immunoanalytical methods.

RESULTS

Preoperative serum levels of CYFRA 21-1, TPA, TPS and CEA were significantly higher in patients with liver metastases of breast cancer in contrast to healthy controls and patients with benign liver lesions (p-value<0.05). Serum levels of CA19-9 and TK were higher in patients with malignancy in comparison with benign liver disease and healthy controls but these differences were not statistically significant.

CONCLUSION

Tumour markers CEA, CYFRA 21-1, TPA and TPS can be recommended as a good tool for differential diagnosis between liver metastases of breast cancer and benign liver lesions.

Prognostic significance of serum immunoglobulin paraprotein in patients with chronic lymphocytic leukemia

The aim of this study was to explore the clinical and other associated laboratory features of chronic lymphocytic leukemia (CLL) patients with immunoglobulin (Ig) paraproteinemia. Serum protein electrophoresis (SPE) and immunofixation electrophoresis (IFE) were performed to measure serum Ig paraprotein. The correlations between serum Ig paraprotein and other prognostic factors were analyzed. Univariate and multivariate Cox regression analyses were used to assess associations between survival time and potential risk factors. In 133 Chinese CLL patients, 27 (20.3%) patients occurred Ig paraproteinemia at diagnosis. According to the correlation analysis, advanced Binet stage (r=0.314, P<0.001), direct antiglobulin test (DAT)-positive (r=0.366, P<0.001), high level of serum β2-microglobulin (β2-MG) (r=0.296, P=0.001) and thymidine kinase (TK) 1 (r=0.227, P=0.037), unmutated immunoglobulin heavy chain variable gene (IGHV) status (r=0.284, P=0.002), ZAP-70-positive (r=0.305, P=0.001), CD38-positive (r=0.284, P=0.002), and cytogenetic abnormalities of del(17p13) or del(11q22.3) (r=0.208, P=0.032) emerged as factors significantly related to the occurrence of Ig paraproteinemia. Survival analysis showed that the patients with Ig paraproteinemia had significantly shorter survival times than the patients without serum Ig paraprotein (P=0.013). Binet stage (P=0.028), high levels of lactate dehydrogenase (LDH) (P=0.004), IgG paraproteinemia (P=0.048), IgM paraproteinemia (P=0.001), ZAP-70-positive (P=0.003), DAT-positive (P=0.013), unmutated IGHV status (P=0.009), and del(17p13) (P=0.001) were the adverse factors in determining overall survival (OS). Del(17p13) (P=0.006), ZAP-70 (P=0.030), and IgM paraproteinemia (P=0.040) were the variables strongly associated with OS by multivariate Cox regression analysis. It was showed that serum Ig paraprotein might be applied for the assessment of prognosis in patients with CLL.

Serum thymidine kinase is associated with gastric adenocarcinoma

Thymidine kinase (TK) plays an essential role in the processing of thymidine within the cell and therefore it is an important marker of proliferation, particularly in tumor cells. The aim of our study was to determine the diagnostic and prognostic importance of TK measurement in gastric adenocarcinoma. The serum level of TK was measured in 72 patients with gastric adenocarcinoma. Serum levels of TK were significantly elevated in gastric adenocarcinoma in comparison with healthy individuals. Also, we have found that there are significant variations in TK serum concentrations when measured that correlate with important variations in clinico-pathological features and prognostic significance (Tab. 2, Ref. 16).

Elevated serum thymidine kinase 1 predicts risk of pre/early cancerous progression

BACKGROUND

Serological thymidine kinase 1 (STK1) is a reliable proliferation marker for prognosis, monitoring tumour therapy, relapse and detection of malignancies. In this study we investigate the use of STK1 in health screening.

METHODS

The concentration of STK1 was determined by a sensitive dot blot ECL assay in 8,135 persons participating in a health screening program.

RESULTS

The frequency of persons with elevated STK1 (<2.0 pM) was 1.1%, representing diseases linked to pre/early cancerous progression. One person with malignancy (gastric carcinoma) was found among persons with elevated STK1, but none of persons with normal STK1 values. There was a significantly higher frequency of persons with moderate/severe type of hyperplasia of breast and prostate expressing elevated STK1, compared to persons with normal STK1 values. No significant difference was found concerning mild hyperplasia. Of persons with elevated STK1, 89.2% had diseases linked to risk for pre/early cancerous progression, compared to 41.2% of persons with normal STK1 values. Among the persons with elevated STK1 values, one developed liver carcinoma after 13 months and five persons showed progression in their disease within 19 months (breast and prostate hyperplasia, HBV infection).

CONCLUSION

Serological TK1 may be a reliable marker for risk assessment of pre/early cancerous progression.

Circulating tumor M2 pyruvate kinase and thymidine kinase 1 are potential predictors for disease recurrence in renal cell carcinoma after nephrectomy

OBJECTIVES

Pyruvate kinase type M2 (TuM2-PK) and thymidine kinase 1 (TK1) are the key enzymes involved in tumor cells metabolism and proliferation. We explored the association of their preoperative circulating levels with disease recurrence in patients with renal cell carcinoma (RCC).

METHODS

We measured the plasma levels of TuM2-PK levels and serum TK1 activity preoperatively in patients with RCC, using a quantitative ELISA, and correlated the results with clinicopathological parameters.

RESULTS

Significantly higher levels of TuM2-PK and TK1 were found in 116 patients with RCC compared with 20 healthy participants (P < .001 and P = .03), but not compared with 27 patients with benign kidney tumors (P = .13 and P = .72). There was a significant association between the level of TuM2-PK and of TK1 activity with T stage (P = .01 and P = .04). Of 2 markers only TuM2-PK was significantly associated with tumor grade (P = .001). The presence of extensive tumor necrosis (> 50%) was associated with high TuM2-PK (P = .001) and low TK1 (P = .03). The 5-year recurrence-free survival for patients with elevated TuM2-PK or TK1 was significantly lower compared with those for patients with normal marker levels (55% vs 94%, P < .001 and 21% vs 90%, P = .002). Multivariate Cox Proportional Hazard analysis demonstrated that TuM2-PK and TK1, adjusted for stage, grade and tumor necrosis were retained as independent predictors of disease recurrence (HR = 7.3, P = .04 and HR = 3.8, P = .03).

CONCLUSIONS

The measurements of 2 circulating biomarkers, TuM2-PK and TK1, in RCC patients before nephrectomy can be useful for predicting recurrence and stratifying the patients into risk groups for possible adjuvant treatment.

Transient increase in serum thymidine kinase 1 within one week after surgery of patients with carcinoma

AIM

To investigate transient increases of thymidine kinase 1 in serum (STK1) after surgery of patients with carcinoma.

PATIENTS AND METHODS

STK1 was determined before and within one week after surgery of carcinoma patients (non-small cell lung (NSCLC), n=25, oesophagueal, n=12, cardial, n=4,) by a chemiluminescent dot blot assay using anti-TK1 IgY antibody.

RESULTS

The mean age of the patients with high STK1 values after surgery was 63.2+/-8.7 years, while that for patients with stable/low STK1 values was 54.8+/-11.8 years; this was significantly different at P<0.05. Sixty-one percent of the patients with high STK1 values after surgery exhibited declining red blood cell (35%) or increasing white blood cell/neutrophil cell (29%) counts. The high STK1 values after surgery correlated with a prolonged operation execution time in anaemic patients (3.43+/-0.90 h), as compared non-anaemic patients (2.72+/-0.79 h). The high STK1 values also correlated with extensive surgery programs (oseophageal/ cardial carcinoma, 3.31+/-0.70 h, versus NSCLC, 2.44+/-0.63 h).

CONCLUSION

The transiently elevated STK1 values post-operation might be due to surgery-induced complications, such as anaemia and infection/inflammation, but also to operation execution times and age of patients. We suggest that STK1 should not be used within one week post-operation, but before surgery and after one month to avoid non-tumor-related increases in STK1, and thus misleading results.

[Development of new methods for the diagnosis of nasopharyngeal carcinoma]

OBJECTIVE

Development of new methods, ELISA and immunostrip test, for the diagnosis of nasopharyngeal carcinoma.

METHODS

The engineering purified antigens coat plate or absorb on nitrocellulose filter. The plate and diagnostic strips carrying antigens were used for detection of IgG antibody in the sera from nasopharyngeal carcinoma patients and outpatients patients.

RESULTS

127 cases sera from nasopharyngeal carcinoma patients were parallel detected TK/IgG antibody by ELISA and immunostrips. The TK/IgG antibody are all positive in the 127 cases of nasopharyngeal carcinoma patients. 55 cases show positive by ELISA, 58 cases positive by immunostrips in 247cases sera from outpatient. The antibody positive rate to early antigen p54 lower then to TK. Conclusion ELISA and imuunostrips are sensitive and specific means for detection of the IgG antibody to TK of EBV and the diagnosis of nasopharyngeal carcinoma.

Test of ovarian cancer multiplex xMAP technology panel

BACKGROUND

An ovarian cancer marker panel including leptin, prolactin, osteopontin, insulin-like growth factor II (IGFII), macrophage migration inhibitory factor and CA125 was tested for multiplex marker measurement. Multiplex was compared to single assayed tumour markers: CA125, TPS, thymidine kinase, monototal and HE4.

PATIENTS AND METHODS

The serum marker levels in ovarian cancer patients were compared to controls with benign ovarian disease. xMAP technology was used for multiplex panel and routine immunoanalytic methods for other markers.

RESULTS

Considering the multiplexed markers, only CA125(Luminex), osteopontin and IGF-II differed significantly between groups. Levels of all non-multiplexed tumour markers were significantly higher in the cancer group compare to the control.

CONCLUSION

Multiplex is a powerful tool for multiparametric studies, but we are still in the era of looking for the right marker combinations for cancer diagnostics and monitoring. The panel will be tested on a larger ovarian cancer cohort and in patients with other cancer and non-cancerous diseases.

[Lipoprotein lipase and serum thymidine kinase level in chronic lymphocytic leukemia and their correlations with other prognostic factors]

OBJECTIVE

To investigate lipoprotein lipase (LPL) and serum thymidine kinase (TK) levels in chronic lymphocytic leukemia (CLL) and their correlations with other prognostic factors.

METHODS

LPL expression level in peripheral blood samples of 58 CLL patients was detected by semi-quantitative reverse transcription PCR (RT-PCR). Serum TK1 level in 39 CLL patients was detected by enhanced chemiluminescence (ECL) and TK monoclonal antibody (Anti-TK mAb). IgVH mutation status was detected by multiplex PCR and sequencing of purified PCR products. The expression of ZAP-70 protein and CD38 were determined by flow cytometry . Panel probes and fluorescence in situ hybridization (FISH) were used to detect cytogenetic aberrations.

RESULTS

The median LPL expression level in CLL was 0.26 (0 -6.29), while undetectable in normal controls. LPL expression level was significantly correlated with IgVH mutation status, Binet stages, CD38 and cytogenetic aberrations. Patients with unmutated IgVH genes had higher LPL than those with IgVH mutations (P = 0.010). Patients in Binet stage B and C had higher LPL than those in stage A (P = 0.011). LPL level was higher in patients with CD38 > or = 30% (P = 0.001). Higher LPL level was found in patients with unfavorable cytogenetic aberrations (deletion in 17p13 or 11q22) than those with favorable cytogenetics (deletion in 13q as the sole abnormality) (P = 0.002). LPL level was not significantly correlated with sex, age, and ZAP-70 protein (P > 0.05). The level of TK1 was higher in CLL patients than that in normal control (P < 0.05). Patients with higher level of absolute lymphocyte count (ALC), lactate dehydrogenase (LDH), unmutated IgVH genes and ZAP-70 had higher levels of TK1 than those with lower level of ALC, LDH, mutated IgVH genes and ZAP-70 (P = 0.018, P = 0.018, P = 0.030 and P = 0.038, respectively). TK1 level had no correlation with sex, age, Binet stages, CD38, and cytogenetic aberrations (P > 0.05).

CONCLUSIONS

LPL expression and serum TK1 levels significantly correlate with other CLL prognostic factors and could be predictive markers for IgVH mutation status. LPL and serum TK1 might be applied to the assessment of prognosis in CLL patients.

Elevated levels of thymidine kinase 1 peptide in serum from patients with breast cancer

OBJECTIVES

Thymidine kinase (TK) has an important role in DNA synthesis and is thus related to cell proliferation and turn-over. Traditionally, TK has been measured by enzymatic activity or radioimmunoassays. These assays are difficult to adapt to random access instruments. The aim of this study was to evaluate a new immunological sandwich assay for detection of TK peptides in serum from breast cancer patients.

MATERIAL AND METHODS

Serum samples were collected from patients with breast cancer and stored frozen at -70 degrees C. The samples were collected after surgery, after metastatic tumor recurrence and after chemotherapy due to tumour recurrence. Patients' serum samples were analysed by the TK enzyme-linked immunosorbent assay (ELISA).

RESULTS

In receiver operating characteristics (ROC) analyses of TK1 for diagnosis of breast cancer, the area under the curve (AUC) collected four weeks after surgery was 0.56 (95% CI 0.47-0.65), for samples collected postsurgically after tumour recurrence 0.73 (95% CI 0.65-0.80), and after chemotherapy 0.64 (95% CI 0.56-0.72).

CONCLUSIONS

This study indicates that the tumour proliferation marker TK has a potential as a serum marker in breast cancer. Further studies are warranted to verify this observation.

Serological thymidine kinase 1 (STK1) indicates an elevated risk for the development of malignant tumours

BACKGROUND

The role of serum tumour markers is to reveal tumours not yet visible by imaging techniques. Here we examine the use of serum thymidine kinase 1 protein (STK1) in health screening.

PATIENTS AND METHODS

Persons (n = 11,880) participating in health screening programs in China, during 2005-2007, were tested for STK1. STK1 was measured by a sensitive chemiluminescence dot-blot assay. Medical examination of participants was carried out in parallel.

RESULTS

The proportion of STK1-positive (> 2 pM) individuals was 0.5%, corresponding to the cancer incidence rate of China. No malignant cases were found in the STK1-negative group, but two pre-malignant and one malignant case were found in the STK1-positive group. The low frequency of malignancies found was probably due to the relatively young population (mean age 40.4 +/- 13.4 years). In the STK1-positive group, there were 24% of persons with benign diseases (breast, liver, kidney), 37% with proliferative tissues (breast, prostate), 13% with fatty liver, 9% with inflammatory reactions/virus infections (three hepatitis B virus-positive persons) and 17% showed other types of physiological changes not directly related to proliferation. In the STK1-positive group, a significantly (p < 0.001) higher proportion of persons with proliferation of breast and prostate tissues were found (37%), as compared to the STK1-negative group (18%). Furthermore, the mean ages among the groups of persons with STK1-positive values were between 5-8 years higher, as compared to the STK1 negative group, due to higher mean ages of persons with proliferative breast and prostate tissues. Thus, 83% of the STK1-positive persons had diseases (benign, proliferation tissues, fatty liver, helicobacter pylori-positive and hepatitis B virus-positive) related to malignancies.

CONCLUSION

STK1-values > 2 pM may indicate an early risk for development of malignancies years later.

[Disturbed metabolism of gastric mucosa DNA precursors as prognosticator of neoplastic transformation of gastric ulcer]

Levels were assayed and compared of metabolic enzymes--thymidine and adenosine--in gastric mucosa tissues and blood serum from patients with gastric ulcer disease and gastric cancer (age--30-60 yrs). Enzymatic levels matched to the highest degree in cases of ulcer disease aggravated by chronic atrophic gastritis and precancerous alterations (dysplasia, metaplasia). Elevated concentrations of thymidine kinase and phosphorylase and adenosine desaminase were identified both at foci of ulceration (p > 0.001, p > 0.05, respectively) and in blood serum in all age brackets. Moreover, blood serum assay confirmed the view that changes in serum enzyme levels are suggestive of those in tissue enzymatic profile. Our data established a direct correlation between accumulated effect of level changes, on the one hand, and risk of neoplastic transformation of gastric mucosa in ulcer patients, on the other.

Prognostic markers in chronic lymphocytic leukaemia

Rai and Binet staging of chronic lymphocytic leukaemia (CLL) is being superseded by new prognostic markers. The mutational status of the immunoglobulin variable region heavy-chain genes segregates the disease into more benign and more malignant versions, and has been confirmed as an important prognostic marker in prospective clinical trials. A search for surrogate markers for this difficult-to-perform assay has led to flow cytometric assays for CD38 and ZAP-70 expression, although in both cases there are problems with standardization and interpretation of the assays. A separate pathway of research has revealed two chromosomal aberrations--deletions of 11q and 17p--as important prognostic markers. Fluorescent in-situ hybridization has made their detection readily available. These five markers are in different stages of evaluation, but some of them are ready to be used for risk-adapted therapy in clinical trials. Other assays are in earlier stages of assessment.

Tumor markers as useful predictors of survival rate after exploratory laparotomy for liver malignancies

BACKGROUND

Tumor markers are used for the prediction of relapse and in determining the effect of postoperative or post-oncological therapy as a standard component of follow-up. Metastatic processes of the liver and primary malignancies of the liver and gall bladder are very common in the European population. The aim of this study was to demonstrate the behaviour of malignancy in patients who have not undergone surgical therapy and to study serum levels of the monitored tumor markers in relation to the life expectancy of these patients.

PATIENTS AND METHODS

The Log-rank test and Wilcoxon test were used for statistical evaluation. Survival was computed using the Kaplan-Meier method. Serum levels of the tumor markers conventionally used in clinical practice in patients with gastrointestinal tumors (CEA, CA19-9, C724) and the markers of the proliferation activity in malignancy (TK, TPA, TPS) were studied.

RESULTS

One hundred and nine patients who underwent exploratory laparotomy without any surgical therapy between September 1999 and June 2005 were studied. For patients with a serum level of CEA, CA19-9 and CA72-4 that was higher than the calculated cut-off hazard ratios of early death were respectively 3-, 5- and 9-fold higher than for patients with serum levels of the same tumor markers below the calculated cut-off. Preoperative serum levels of proliferative tumor markers (TK, TPA and TPS) were not statistically significant for the prediction of early death.

CONCLUSION

The results of the pilot study suggest the importance of tumor markers for the prediction of the short-term survival rate. These markers could be used to supplement classic clinical, laboratory and radiodiagnostic parameters. It would be very helpful for the planning of palliative oncological therapy for patients with liver malignancies who cannot be treated by surgical therapy.

Prognostic importance of thymidine kinase in colorectal and breast cancer

BACKGROUND

Thymidine kinase (TK) plays an essential role in the processing of thymidine within the cell and therefore it is an important marker of proliferation, particularly in tumor cells. The aim of our study was to determine the diagnostic, prognostic and predictive importance of TK measurement in cancer.

PATIENTS AND METHODS

TK was measured using radioreceptor analysis (RRA) with Immunotech assay kits. The serum level of TK was measured in 1087 patients with malignant disease (355 patients with hematology malignancies and 732 patients with solid tumors).

RESULTS

Serum levels of TK were significantly elevated in inflammatory and immunological diseases in comparison with healthy individuals. Malignant diseases were associated with elevated serum levels of TK only in particular cases (e.g. hematological malignancies, cervical cancer). This marker has a high sensitivity for use as a primary diagnostic tool. It also has a high sensitivity during the follow-up period in breast and colorectal cancer for the prediction of relapse at the time of primary diagnosis and 3 months earlier than the diagnosis of relapse by imaging methods.

CONCLUSION

TK represents a secondary tumor marker which is particularly useful for cancer disease monitoring. Interpretation of this marker must be performed only in association with evaluation of clinical status since all other possible non-specific causes (inflammatory or immunological diseases) of elevated serum levels must be excluded.

Changes of serum thymidine kinase in children with acute leukemia

BACKGROUND

Thymidine kinase (TK) is involved in nucleic acid synthesis and is therefore considered to be an important proliferation tumor marker. Our main goal was to determine the significance of elevated TK levels as a relapse marker during follow-up with child patients suffering from acute leukemia.

PATIENTS AND METHODS

TK serum levels in 38 children with acute leukemia (34 lymphoblastic, 4 myeloblastic) were determined using radio-receptor analysis (RRA, Immunotech, Prague, USA). All patients included in this study had had TK examined before the start of the treatment and at least twice during the follow-up.

RESULTS

Our results showed that TK serum levels at the time of diagnosis were extremely high (78-5826 U/l, median value 403 U/l, normal < 8 U/l), while in remission TK serum levels were much lower (5-80 U/l, median value 31 U/l). During relapse of acute leukemia (5 cases), TK levels increased considerably to measurements between 120-800 U/l (median value 324 U/l). The study showed that the elevation of TK serum levels during follow-up was a helpful marker for the recognition of an early stage of relapse and in some cases occurred as early as one month before the appearance of clinical signs. Sensitivity in this case was 87% and thus TK serum levels seem to be a very good parameter during follow-up because of acceptable sensitivity, low cost (4 $/sample) and the elimination of a requirement for screening of bone marrow samples.

CONCLUSION

While TK serum levels were helpful in predicting relapse during follow-up, it is necessary to note that they did not correlate with prognosis in our group of patients during the time of the initial diagnosis of acute leukemia.

Thymidine kinase 1 in serum predicts increased risk of distant or loco-regional recurrence following surgery in patients with early breast cancer

BACKGROUND

The prognostic value of the concentration of serum thymidine kinase 1 (S-TK1) with regard to recurrence in low risk breast cancer patients, 3 months after surgery was evaluated.

PATIENTS AND METHODS

The concentration of S-TK1 in serum was determined in 120 breast cancer patients at the time of surgery and in 67 patients 3 months after surgery, by anti-TK1 chicken IgY antibody, using a dot-blot immuno-assay. The S-TK1 concentration was compared with the serological activity of thymidine kinase (STK) and of carbohydrate antigen (CA 15-3).

RESULTS

A statistically significant trend (unadjusted) was found for recurrence (distant or loco-regional) in patients with a higher S-TK1 concentration, as compared with patients with a lower S-TK1 concentration. A multivariate analysis gave the same results. The hazard rate ratio for developing distant and/or loco-regional recurrence in patients with a higher S-TK1 concentration was about six to seven times higher than in patients with a lower S-TK1 concentration.

CONCLUSION

Our results indicate that the S-TK1 concentration is higher in patients developing distant and/or loco-regional recurrence 3 months post-surgery.

Serum TK levels in CLL identify Binet stage A patients within biologically defined prognostic subgroups most likely to undergo disease progression

OBJECTIVE

Serum thymidine kinase (TK) levels have been shown to be correlated with survival in many malignancies, including chronic lymphocytic leukaemia (CLL). This study was designed to investigate associations between TK levels and other prognostic markers, in newly and previously diagnosed Binet stage A patients. Furthermore, the use of serum TK measurement to identify subcategories of disease within those defined by IgV(H) mutational status, gene usage and chromosomal aberrations was investigated.

METHODS

Ninety-one CLL patients were enrolled. Serum TK levels were measured using a radioenzyme assay. IgV(H) mutational status and V(H) gene usage were determined using BIOMED-2 primers and protocol. Recurring chromosomal abnormalities were detected by interphase fluorescent in situ hybridisation (FISH). Flow cytometry and reverse transcriptase polymerase chain reaction (RT-PCR) determined CD38 and Zap-70 expression, respectively.

RESULTS

Significantly higher serum TK levels were found in IgV(H) unmutated, compared with IgV(H) mutated, patients (P < 0.001). Elevated TK levels were also found in patients with CD38 and Zap-70 positivity (P = 0.004, P < 0.001, respectively), short lymphocyte doubling time (LDT) (P = 0.044) and poor or intermediate prognosis chromosomal aberrations (P < 0.001).

CONCLUSION

A TK level of >8.5 U/L best identified patients with progressive disease. Elevated TK levels could identify patients categorised, at diagnosis, into good prognosis subgroups by the various biological markers (mutated IgV(H), good prognosis chromosomal aberrations, Zap-70(-) and CD38(-)) who subsequently showed disease progression. Additionally, patients with V(H)3-21 gene usage showed high TK levels, irrespective of mutational status, and serum TK measurement retained predictive power as disease progressed in all subcategories studied.

Early prediction of therapy response in patients with acute myeloid leukemia by nucleosomal DNA fragments

BACKGROUND

Elevated levels of nucleosomal DNA fragments can be detected in plasma and sera of patients with malignant diseases.

METHODS

We investigated the course of nucleosomal DNA, thymidine kinase, lactate dehydrogenase and leukocytes in sera of 25 patients with acute myeloid leukemia during the first cycle of induction chemotherapy and tested their power to distinguish between patients with complete remission and those with no remission.

RESULTS

Almost all patients showed strongly decreasing levels of nucleosomal DNA during the first week, in some cases after initial peaks. In overall analysis of variance, DNA levels could clearly distinguish between patients with complete remission, who had higher DNA values, and those with insufficient response (p = 0.017). The area under the curve of DNA values of days 2-4 after start of therapy (AUC 2-4) discriminated between both groups with a sensitivity of 56% at a specificity of 100%. Further, pretherapeutic levels and AUC 2-4 of nucleosomal DNA correlated significantly with blast reduction after 16 days. A tendency to higher levels in patients with complete response was also found for thymidine kinase, lactate dehydrogenase and leukocytes, however the difference did not reach the level of significance (p = 0.542, p = 0.260, and p = 0.144, respectively).

CONCLUSION

Our results indicate that nucleosomal DNA fragments are valuable markers for the early prediction of therapeutic efficacy in patients with acute myeloid leukemia.

Thymidine kinase 1: a proliferation marker for determining prognosis and monitoring the surgical outcome of primary bladder carcinoma patients

Reliable markers for monitoring bladder tumor therapy are needed to evaluate treatment effectiveness. Thymidine kinase 1 (TK1) is an enzyme involved in DNA synthesis and therefore proliferation-dependent. Serum concentration of TK1 (STK1) correlates with malignancy in various types of cancer, thus reflecting treatment results. This study explores for the first time the use of STK1 concentration, both as a prognostic marker and to monitor the outcome of bladder carcinoma surgery. STK1 in 56 bladder carcinoma patients was measured pre-operatively, and post-operatively at 1 week and 1, 3, and 6 months, using an immune ECL dot blot assay. An anti-TK1 chicken IgY antibody was used to determine STK1 concentrations. Mean pre-operative STK1 of bladder carcinoma patients was significantly higher than that of healthy individuals, with no overlap of individual values. STK1 concentrations increased significantly with tumor stage (I-III) and T-values (T1-T2), but not tumor grade (G1-G4). STK1 gradually declined, being 66% lower after 1 week. STK1 reached the level of healthy controls at 1 month and remained there for at least 6 months, post-operatively until this study ended. Since STK1 concentration correlates with tumor stage, degree of invasion and metastasis, and monitors the surgical outcome, it can be a reliable index to diagnose and determine prognosis in post-operative bladder carcinoma.

A non-radiometric method for measuring serum thymidine kinase activity in malignant lymphoma in dogs

The aim of this study was to evaluate an enzyme-linked immunosorbent assay (ELISA), for determination of serum thymidine kinase 1 (sTK1) activity in dogs with malignant lymphoma (ML) and compare it with a thymidine kinase (TK) radioenzymatic assay (TK-REA). The TK-REA has recently been shown to be useful in determining the clinical stage and prognosis in canine ML. In addition, serum lactate dehydrogenase (LDH) was measured. Forty-five dogs were included in the study. Sixty serum samples from these dogs, stored in a tumour serum sample bank (stored at -20 degrees C), were analysed. Apart from 37 dogs with ML, four normal dogs as well as two dogs with mammary carcinomas, one dog with bladder carcinoma, and one dog with malignant fibrous histiocytoma were included. Staging of ML was based on the modified World Health Organization (WHO) staging system for canine ML. The diagnosis of all tumours was verified by histopathology. The TK activity (units per litre [U/L]) ranged from 1.0 to 607.9 in the TK-REA analysis and from 1.1 to 510 in the TK-ELISA (normal reference value <7U/L). The range for LDH was between 12 and 1194 U/L (normal reference value <228 U/L). There was a significant correlation between the TK-REA and the TK-ELISA. The correlation coefficient (CC) was 0.97 and the standard error of the estimate (SEE) was 3.7 U/L. There was no correlation between LDH and either the TK-REA or the TK-ELISA (CC=0.53 for both assays; SEE=26.7 and 12.7 U/L, respectively). Most of the variation in LDH was still within the normal reference range. The mean LDH in dogs with high-stage (stage IV+V) disease was 201.9 U/L. The corresponding values for the TK-REA and TK-ELISA were 109 and 109.9 U/L, respectively. The significant relation between the TK-REA and the TK-ELISA was confirmed by Bland-Altman analysis. The TK-ELISA assay, because of its relative simplicity, will permit measurement of TK in cases of ML in dogs to become a routine procedure.

Immunosuppressive treatment for mixed connective tissue disease may facilitate the development of adult T cell leukemia/lymphoma in a HTLVI carrier

A 66-year-old woman who was positive for human T-lymphotropic virus type I (HTLV-I) antibody developed mixed connective tissue disease (MCTD) with interstitial pneumonia, and was successfully treated with corticosteroid. One year later, under maintenance treatment of prednisolone (PSL), she contracted acute type adult Tcell leukemia/lymphoma (ATLL) without flaring of MCTD. MCTD is considered to be as one of the HTL-V-I-related inflammatory diseases, however the development of ATLL during the treatment of HTL-V-I-related MCTD has not been well studied. Here, we review the literature and raise the issue of the mutual interactions between MCTD-causative anti-HTLV-I immune response and anti-ATLL immune response.

Concentration of thymidine kinase 1 in serum (S-TK1) is a more sensitive proliferation marker in human solid tumors than its activity

Activity of thymidine kinase 1 in serum (STK) is a useful marker for leukaemia and lymphoma, but not for solid tumors. We investigate thymidine kinase 1 concentration in serum (S-TK1) as a potential tumor marker. S-TK1 concentration and STK activity levels were determined in 9 human malignant diseases (breast, gastric, rectal, colorectal, lung, brain cancer, hepatoma, lymphoma, leukaemia) and in benign and non-cancerous diseases, representing 850 preoperative cases. Healthy volunteers (n=43) were used as positive controls. S-TK1 concentration was determined by ECL dot blot assay and STK activity levels by an RIA assay. S-TK1 concentrations and STK activity levels in preoperative malignant patients were significantly higher than in healthy individuals, in patients with benign tumors and in those with non-cancerous diseases. Significant correlations between concentration and activity level were only found in healthy individuals, in patients with benign tumors, and in some patients with malignancies, i.e. leukaemia, and breast and gastric cancers. About 90-95 percent of the malignant patients showed S-TK1 concentrations above those of the healthy controls. The corresponding value for STK activity was about 75 percent. When sera from malignant patients were diluted with sera from healthy individuals, S-TK1 concentrations and STK activity levels decreased more than expected. This indicates the presence of a compound (or compounds) in the serum of healthy individuals that destabilises S-TK1. We conclude that S-TK1 concentration is a more sensitive tumor marker in solid malignancies than is STK activity.

Serum thymidine kinase 1 is a prognostic and monitoring factor in patients with non-small cell lung cancer

Thymidine kinase 1 (TK1) is a pyrimidine metabolic pathway enzyme involved in salvage DNA synthesis and thus, a cell cycle-dependent marker. We have developed anti-TK1 monoclonal/polyclonal Abs raised against a 15-amino acid synthetic peptide (KPGEAVAARKLFAPQ) corresponding to part of the C-terminus of human TK1. These Abs are useful for both serological and immunohistochemical detection of TK1 in a number of cancer diseases. In this study we examined TK1 concentration in serum (STK1) in 250 preoperative non-small cell lung cancer patients (NSCLC), including 188 non-metastatic (group M0) and 62 metastatic patients (group M1). Serum from 16 healthy individuals was used as controls. The concentration of STK1 of preoperative NSCLC patients was significantly higher than STK1 of healthy individuals (p<0.0001). In group M0, preoperative STK1 concentration was significantly higher in patients of tumour size T2, as compared to tumour size T1 (p=0.042), and in T3-T4, as compared to T1-T2 (p=0.01). No significant difference in STK1 concentration between patients of tumour stage I and stage II (p=0.057) were found, but significantly higher STK1 concentration in patients of stage III, as compared stage I-II (p=0.025). No significant difference of STK1 concentration were found in patients of group M1 concerning tumour size or tumour stage, or between patients with adenocarcinomas (AC) and squamous cell carcinomas (SCC). We studied the changes of STK1 concentration individually one month after operation in metastatic subjects (group M1, n=19) and in tumour-free subjects (group M0, n=38). In the M0 group, the concentration of STK1 one month after operation was significantly decline by 45%, when comparing to concentrations of STK1 preoperative (p<0.001). In the group M1, however, no significant decrease in STK1 concentrations were found one month after operation. We conclude that STK1 has prognostic value and is a reliable marker for monitoring the response to surgery of NSCLC patients.

Serum thymidine kinase activity in dogs with malignant lymphoma: a potent marker for prognosis and monitoring the disease

Serum thymidine kinase (sTK) activity was evaluated as a tumor marker for canine malignant lymphoma (ML). The objective was to investigate if sTK, as in humans, could be used as a prognostic marker for survival time in dogs with ML and if sTK could identify early signs of progression of disease in treated dogs. Serum samples from 52 dogs with ML were tested for initial TK activity. Samples from 21 normal dogs and 25 dogs with nonhematologic neoplasms were used for comparison. Forty-four dogs with ML were treated. Serum TK activity was measured in treated dogs before each treatment and every 4 weeks thereafter until relapse. Dogs with ML had 2-180 times higher TK activity (TK 5-900 U/L) than normal dogs (TK <7 U/L) based on the mean + 2 standard deviations. In the group of other neoplasms, only 2 dogs had a moderate increase (6.4 and 7.5 U/L) compared with the controls. Mean sTK activities in the dogs with ML that had gone into complete remission (CR) were not significantly different from activities in healthy controls (P = .68). Mean sTK at least 3 weeks before and at the time of relapse was significantly higher than activity measured at CR (P < .0001). Dogs with ML that initially had sTK >30 U/L had significantly shorter survival times (P < .0001). Furthermore, sTK activity reflected the clinical staging of ML. Measuring sTK can be used as a powerful objective tumor marker for prognosis and for predicting relapse before recurrence of clinically detectable disease in dogs with ML undergoing chemotherapy.

Serum thymidine kinase activity: an alternative to histologic markers of cellular proliferation in canine lymphoma

Thymidine kinase (TK) is a cellular enzyme which is involved in a 'salvage pathway' of DNA synthesis. It is activated in the G1/S phase of the cell cycle, and its activity has been shown to correlate with the proliferative activity of tumor cells.... Clinical studies have reported high serum TK concentrations in a variety of neoplasias. The majority of these studies concerned hematological malignancies. TK seems to be a useful marker in non-Hodgkin's lymphoma, where it correlates with clinical staging and provides marked prognostic information on (progression-free) survival.

Sensitive nonradiometric method for determining thymidine kinase 1 activity

BACKGROUND

Thymidine kinase 1 (TK1) is a cytoplasmic enzyme, produced only in the S-phase of proliferating cells, that has potential as a tumor marker. Specific determination of TK1 in serum is difficult, in part because of differences in the physical properties of serum TK1 compared with cytoplasmic TK1.

METHODS

The first step in the new assay was phosphorylation of 3'-azido-2',3'-deoxythymidine (AZT) to AZT 5'-monophosphate (AZTMP) by TK1 present in patient material. The AZTMP formed was measured in a competitive immunoassay with specific anti-AZTMP antibodies and AZTMP-labeled peroxidase. Results were compared with those of a TK radioenzyme assay (REA) for 78 samples from patients suffering from hematologic diseases.

RESULTS

The detection limit was 78 microIU/L, and within-run CVs <20% were seen for samples with TK1 down to 130 microIU/L. Cross-determination of the mitochondrial isoenzyme TK2 activity was <0.1%. Between-assay imprecision (CV) was 3.5-7.4%, and the within-assay imprecision was 4.1-9.1%. In studies of recovery and linearity on dilution, measured values ranged from 84% to 115% of expected at concentrations of 0.26-10.4 mIU/L. Results of the new assay (mIU/L) = 0.109 x TK REA (U/L) + 0.092. Heterophilic antibodies did not interfere in the assay. The upper 95th percentile, in 100 healthy individuals, was 0.94 mIU/L, and the median value was 0.43 mIU/L.

CONCLUSION

The TK1 enzyme-labeled immunoassay uses a stable substrate, is precise, appears to be accurate, and is resistant to interferences. It may provide a practical tool in the management of hematologic malignancies.

Lack of reduction of thymidine kinase activity in stavudine-treated HIV-infected patients

It has been demonstrated that prolonged in vivo or in vitro treatment with some nucleosides analogs may favor the selection of cells with a reduced activity of enzymes involved in the phosphorylation of these drugs leading to a reduced sensitivity to their antiretroviral action. The aim of this study was to evaluate the effect, in vivo, of zidovudine and stavudine treatment on thymidine kinase (TK) activity. The results obtained showed that TK levels in PBMC from naive patients and stavudine-treated patients did not significantly differ (naive TK = 4.16 +/- 1.19 U/mg protein; stavudine TK = 3.65 +/- 1.73 U/mg protein; p = 0.42), suggesting that the treatment with this nucleoside analog is not associated to a defect of TK activity. On the contrary, PBMC from zidovudine-treated patients showed a significant reduction in TK activity compared to naive patients (naive TK = 4.16 +/- 1.19 U/mg protein; zidovudine TK = 2.70 +/- 1.54; p = 0.014. Although the clinical significance of these results has to be established, we can speculate that stavudine and zidovudine, which are presumably phosphorylated by the same cellular kinases, might display a different ability to in vivo select cells with a resistant phenotype.

ZAP-70 expression is a prognostic factor in chronic lymphocytic leukemia

B-cell chronic lymphocytic leukemia (B-CLL) is a heterogenous disease with a highly variable clinical course. Recent studies have shown that expression of the protein tyrosine kinase ZAP-70 may serve as a prognostic marker in B-CLL. Employing a semiquantitative RT-PCR assay, we examined purified leukemia B cells of 39 CLL patients for the expression of ZAP-70 mRNA transcripts. Significant ZAP-70 mRNA levels exceeding those found in control samples with 5% T cells were detected in 36% of the CLL cases. Patients in the ZAP-70 positive cohort were characterized by an unfavorable clinical course with a significantly shorter progression-free survival as compared to the ZAP-70-negative patients (64%). These results were confirmed by flow-cytometric analysis of the ZAP-70 protein, and expanded to a larger patient cohort (n=67). A combined statistical analysis of 79 patients showed that the two patient subgroups also differed with regard to overall survival and a panel of known clinical prognostic factors including LDH, thymidine kinase serum levels and expression of the CD38 surface antigen by the leukemic cell clone. The level of ZAP-70 expression did not change over time in the majority of patients where sequential samples were available for analysis.

Production and characterisation of a novel chicken IgY antibody raised against C-terminal peptide from human thymidine kinase 1

Egg yolk is a good source of highly specific antibodies against mammalian antigens because of the phylogenetic distance between birds and mammals. Chicken egg yolk immunoglobulins (IgY) were generated to a synthetic 31-amino acid peptide from the C-terminal of human HeLa thymidine kinase 1 (TK1) enzyme. The anti-TK1 IgY antibody was purified using affinity chromatography against the 31-amino acid peptide. The purified antibody inhibited the catalytic activity of the TK1 enzyme in the CEM TK1(+) cells and recognized the 25-kDa subunit and tetrameric form of TK1, which has a pI value of 8.3. No immunoreaction was observed in CEM TK1(-) cells. Western blot of the serum TK1 (S-TK1) also showed that only a single band was found in the serum of patients with malignancies. No band was seen in healthy serum. Furthermore, dot blots and enhanced chemiluminescence (ECL) detection of S-TK1 performed on sera of preoperative patients with gastric cancer (GC) (n=31) and healthy controls (n=62) showed that the levels of S-TK1 in the sera of cancer patients were significantly different (P<0.01). Using ECL dot blots, 0.1 pg of TK1 in 3 microl sera could be detected. Immunohistostaining of tissues in the 11 advanced-stage cancer patients (four breast carcinomas, three hepatocarcinomas and four thyroid carcinomas) indicated that a strong staining of TK1 enzyme was found in the cytoplasm of malignant cells. No staining or weak staining was seen in normal tissues. We suggest that screening for TK1 using anti-TK1 IgY may be potentially useful for serological and immunohistochemical detection of TK1 as an early prognosis and for monitoring patients undergoing treatment.