Evaluation of 3'-deoxy-3'-[18F]-fluorothymidine (18F-FLT) kinetics correlated with thymidine kinase-1 expression and cell proliferation in newly diagnosed gliomas.
Eur J Nucl Med Mol Imaging
; 40(2): 175-85, 2013 Jan.
Article
em En
| MEDLINE
| ID: mdl-23229746
ABSTRACT
PURPOSE:
The thymidine analog 3'-deoxy-3'-[(18)F]fluorothymidine ((18)F-FLT) has been developed as a positron emission tomography (PET) tracer to assess the proliferation activity of tumors in vivo. The present study investigated the relationship between the kinetic parameters of (18)F-FLT in vivo and thymidine kinase-1 (TK-1) expression and cell proliferation rate in vitro, and blood-brain barrier (BBB) breakdown in human brain gliomas.METHODS:
A total of 21 patients with newly diagnosed gliomas were examined by (18)F-FLT PET kinetic analysis. Maximum standardized uptake value (SUVmax) and tumor-to-normal (T/N) ratio of (18)F-FLT in the tumor and (18)F-FLT kinetic parameters in the corresponding contralateral region were determined. The expression levels of TK-1 protein and mRNA were determined by immunohistochemistry (IHC) and real-time polymerase chain reaction (PCR), respectively, using surgical specimens. The cell proliferation rate of the tumor was determined in terms of the Ki-67 labeling index. BBB breakdown was evaluated on MR images with contrast enhancement.RESULTS:
(18)F-FLT SUVmax and T/N ratio were significantly correlated with the influx rate constant (K (1); P = 0.001 and P < 0.001, respectively), but not with the phosphorylation rate constant (k (3)). IHC and real-time PCR studies demonstrated a significant correlation between K (1) and TK-1 mRNA expression (P = 0.001), but not between k (3) and TK-1 protein and mRNA expression. Linear regression analysis revealed a significant correlation between K (1) and the Ki-67 index (P = 0.003), but not between k (3) and the Ki-67 index. TK-1 mRNA expression was significantly correlated with the Ki-67 index (P = 0.009). (18)F-FLT SUVmax and T/N ratio were significantly correlated with BBB breakdown evaluated by contrast enhancement in MR images (P = 0.003 and P = 0.011, respectively).CONCLUSION:
These results indicate that (18)F-FLT uptake in the tumor is significantly related to transport through the disrupted BBB, but not through phosphorylation activity. Although the tissue TK-1 expression reflects tumor proliferation activity, the phosphorylation rate constant k (3) determined by (18)F-FLT PET kinetic analysis does not accurately reflect TK-1 expression in the tissue and should not be used as a surrogate biomarker of cell proliferation activity in human brain gliomas.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Timidina Quinase
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Neoplasias Encefálicas
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Didesoxinucleosídeos
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Regulação Enzimológica da Expressão Gênica
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Regulação Neoplásica da Expressão Gênica
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Glioma
Tipo de estudo:
Diagnostic_studies
Limite:
Adult
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Aged
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Ano de publicação:
2013
Tipo de documento:
Article