3′-Deoxy-3′-[ 18 F]fluorothymidine ([ 18 F]FLT) has been proposed as a new marker for imaging tumor proliferation by positron emission tomography (PET). The uptake of [ 18 F]FLT is regulated by cytosolic S-phase-specific thymidine kinase 1 (TK1). In this article, we have investigated the use of [ 18 F]FLT to monitor the response of tumors to antiproliferative treatment in vivo . C3H/Hej mice bearing the radiation-induced fibrosarcoma 1 tumor were treated with 5-fluorouracil (5-FU; 165 mg/kg i.p.). Changes in tumor volume and biodistribution of [ 18 F]FLT and 2-[ 18 F]fluoro-2-deoxy-d-glucose ([ 18 F]FDG) were measured in three groups of mice ( n = 8–12/group): ( a ) untreated controls; ( b ) 24 h after 5-FU; and ( c ) 48 h after 5-FU. In addition, dynamic [ 18 F]FLT-PET imaging was performed on a small animal scanner for 60 min. The metabolism of [ 18 F]FLT in tumor, plasma, liver, and urine was determined chromatographically. Proliferation was determined by staining histological sections for proliferating cell nuclear antigen (PCNA). Tumor levels of TK1 protein and cofactor (ATP) were determined by Western blotting and bioluminescence, respectively. Tumor [ 18 F]FLT uptake decreased after 5-FU treatment (47.8 ± 7.0 and 27.1 ± 3.7% for groups b and c , respectively, compared with group a ; P 18 F]FLT uptake was significantly more pronounced than that of [ 18 F]FDG. The PET image data confirmed lower tumor [ 18 F]FLT retention in group c compared with group a , despite a trend toward higher radiotracer delivery for group c . Other than phosphorylation in tumors, [ 18 F]FLT was found to be metabolically stable in vivo . The decrease in tumor [ 18 F]FLT uptake correlated with the PCNA-labeling index ( r = 0.71, P = 0.031) and tumor volume changes after 5-FU treatment ( r = 0.58, P = 0.001). In this model system, the decrease in [ 18 F]FLT uptake could be explained by changes in catalytic activity but not translation of TK1 protein. Compared with group a , TK1 levels were lower in group b (78.2 ± 5.2%) but higher in group c (141.3 ± 9.1%, P a to b to c ( P 18 F]FLT and PET. In our model system, the radiotracer uptake was correlated with PCNA-labeling index. The decrease in [ 18 F]FLT uptake after 5-FU was more pronounced than that of [ 18 F]FDG. [ 18 F]FLT is, therefore, a promising marker for monitoring antiproliferative drug activity in oncology that warrants additional testing.

https://cancerres.aacrjournals.org/content/canres/63/13/3791.full.pdf

3'-deoxy-3'-[18F]fluorothymidine as a new marker for monitoring tumor response to antiproliferative therapy in vivo with positron emission tomography.

Various methods are available for the measurement of proliferation rates in tumours, including mitotic counts, estimation of the fraction of cells in S-phase of the cell cycle and immunohistochemistry of proliferation-associated antigens. The evidence, advantages and disadvantages for each of these methods along with other novel approaches is reviewed in relation to breast cancer. The potential clinical applications of proliferative indices are discussed, including their use as prognostic indicators and predictors of response to systemic therapy.

/pdf/measuring-proliferation-in-breast-cancer-practicalities-and-4u923eaoqx.pdf

Measuring proliferation in breast cancer: practicalities and applications.

Substrate specificity and phosphorylation of antiviral and anticancer nucleoside analogues by human deoxyribonucleoside kinases and ribonucleoside kinases.

Experimental tumors have great importance in modeling, and Ehrlich ascites carcinoma (EAC) is one of the commonest tumors EAC is referred to as an undifferentiated carcinoma and is originally hyperdiploid, has high transplantable capability, no-regression, rapid proliferation, shorter life span, 100% malignancy and also does not have tumor-specific transplantation antigen (TSTA) Frequently, tumor virulence increases via repetitious passages, while the proliferating rate of such tumors increases gradually However, the differentiation gradually disappears, while the cells get free growth control mechanisms, gain hetero-transplantability and in the end, they are converted to the ascites’ form EAC resembles human tumors which are the most sensitive to chemotherapy due to the fact that they are undifferentiated and that they have a rapid growth rate The ideal drug being ineffective or minimally effective for normal cells have been focused on, and at this point, the usage of natural sources as an alternative cancer therapy is thought to have a great value for cancer control and programs’ destruction Key words : carcinoma, transplantability

/pdf/ehrlich-ascites-carcinoma-36w3c2qzb5.pdf

Ehrlich ascites carcinoma

Purpose: Genetic polymorphisms of DNA repair genes seem to determine the DNA repair capacity, which in turn may affect the risk of breast cancer. To evaluate the role of genetic polymorphisms of DNA repair genes in breast cancer, we conducted a hospital-based case-control study of Korean women. Experimental Design: We included 872 incident breast cancer cases and 671 controls recruited from several teaching hospitals in Seoul from 1995 to 2002. Twelve loci of selected DNA repair genes were genotyped by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry ( XRCC2 Arg 188 His, XRCC4 921G > T, XRCC6 1796G > T, LIG4 1977T/C, RAD51 135G > C, 172G > T, RAD52 2259C > T, LIG1 551A > C, ERCC1 8092A > C, 354C > T, hMLH1 −93G > A, and Ile 219 Val). Results: We found that the RAD52 2259 CT or TT, hMLH1 −93 GG, and ERCC1 8092 AA genotypes were associated with breast cancer risk after adjustment for known risk factors [odds ratio (OR), 1.33; 95% confidence interval (95% CI), 1.02-1.75; OR, 1.31; 95% CI, 0.99-1.74; and OR, 0.58; 95% CI, 0.38-0.89, respectively]. When Bonferroni9s method was used to correct for multiple comparisons for nine polymorphisms with P = 0.005, all of these associations were not significant. However, the effects of RAD52 2259 CT or TT and ERCC1 354 CT or TT genotypes were more evident for the estrogen/progesterone receptor–negative cases (OR, 2.03; 95% CI, 1.24-3.34 and OR, 1.99; 95% CI, 1.35-2.94, respectively). Conclusion: Our findings suggest that genetic polymorphisms of RAD52, ERCC1 , and hMLH1 may be associated with breast cancer risk in Korean women.

https://clincancerres.aacrjournals.org/content/clincanres/11/12/4620.full.pdf

Genetic polymorphisms of selected DNA repair genes, estrogen and progesterone receptor status, and breast cancer risk

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

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 o...

https://journals.sagepub.com/doi/pdf/10.1177/172460080001500203

The clinical significance of thymidine kinase 1 measurement in serum of breast cancer patients using anti-TK1 antibody.

Characterization of a peptide antibody against a C-terminal part of human and mouse cytosolic thymidine kinase, which is a marker for cell proliferation

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.

/pdf/thymidine-kinase-1-a-proliferation-marker-for-determining-4s0qxu7mtl.pdf

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

The cytosolic thymidine kinase 1 (TK1) is one of the enzymes involved in DNA replication. Based on biochemical studies, TK1 is activated at late G1 of cell cycle, and its activity correlates with the cell proliferation. We have developed a polyclonal anti‐TK1 antibody against a synthetic peptide from the C‐terminus of human TK1. Using this antibody, here we demonstrate the exclusive location of TK1 in the cytoplasm of cells. Cell cycle dependent TK1 expression was studied by simultaneous fluorescence staining for TK1 and bromodeoxyuridine, by using elutriated cells, and by quantitation of the amount TK1 in relation to the cellular DNA content. TK1, which was strongly expressed in the cells in S+G2 period, raised at late G1 and decreased during mitosis. The amount of TK1 increased three folds from late G1 to G2. TK1 positive cells were demonstrated in areas of proliferation activity of various normal and malignant tissues. The new anti‐TK1 antibody works in archival specimens and is a specific marker of cell proliferation.

/pdf/investigation-on-cell-proliferation-with-a-new-antibody-59kuo0a2um.pdf

Qimin He

Papers

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

The clinical significance of thymidine kinase 1 measurement in serum of breast cancer patients using anti-TK1 antibody.

Characterization of a peptide antibody against a C-terminal part of human and mouse cytosolic thymidine kinase, which is a marker for cell proliferation

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

Investigation on cell proliferation with a new antibody against thymidine kinase 1.