Elevated plasma deoxyuridine in patients with thymidine phosphorylase deficiency.
 Nonstandard abbreviations: MNGIE, mitochondrial neurogastrointestinal encephalomyopathy; TP, thymidine phosphorylase; dThd, thymidine; and dUrd, deoxyuridine.
Studies about thymidine phosphorylase
and thymidylate synthase concluded that the expression of these markers could be associated with response to just chemotherapy in rectal cancers, with no considerations about survival differences.
Fujimoto et al., "Expression of thymidylate synthase, thymidine phosphorylase, dihydropyrimidine dehydrogenase, E2F-1, Bak, Bcl-X, and Bcl-2, and clinical outcomes for gastric cancer patients treated with bolus 5-fluorouracil," Oncology Reports, vol.
Shiratori, "The ratio of thymidine phosphorylase to dihydropyrimidine dehydrogenase in tumour tissues of patients with metastatic gastric cancer is predictive of the clinical response to 5/-deoxy-5-fluorouridine," European Journal of Cancer, vol.
Thirty-four proteins in our study have been reported as constituents of the normal urine, while 11 proteins (antithrombin-III, alpha-amylase 1, U3 small nucleolar RNA-associated protein 18 homolog, thymidine phosphorylase, endonuclease domain-containing 1 protein, E3 ubiquitin-protein ligase rififylin, quinone oxidoreductase-like protein 1, interleukin enhancer-binding factor 2, transmembrane and immunoglobulin domain-containing protein 1, Ras-related protein Rab-36, and Tumor protein D52) were not reported in the normal urine proteome .
Thymidine phosphorylase (TYMP) is an enzyme involved in pyrimidine metabolism and also known to be a platelet-derived endothelial cell growth factor (PD-ECGF).
Sumizawa et al., "The role of thymidine phosphorylase, an angiogenic enzyme, in tumor progression," Cancer Science, vol.
Leichman et al., "High basal level gene expression of thymidine phosphorylase
(platelet-derived endothelial cell growth factor) in colorectal tumors is associated with nonresponse to 5-fluorouracil," Clinical Cancer Research, vol.
MDDSs cause a reduction in cellular mtDNA content (2).At the present time, mutations in at least 9 genes [POLG,  polymerase (DNA directed), gamma; DGUOK, deoxyguanosine kinase; TK2, thymidine kinase, mitochondrial; TYMP, thymidine phosphorylase; MPV17, MpV17 mitochondrial inner membrane protein; SUCLA2, succinate-CoA ligase, ADP-forming, beta subunit; SUCLG1, succinate-CoA ligase, alpha sub unit; RRM2B, ribonucleotide reductase M2 B (TP53 inducible); C10orf2, chromosome 10 open reading frame 2 (also known as TWINKLE)] have been found to cause mtDNA depletion (3-17).
The predominantly gastrointestinal form of MDDS, mitochondrial neurogastrointestinal encephalomyopathy (MNGIE), is caused by a thymidine phosphorylase deficiency due to TYMP mutations and primarily affects smooth muscle and the brain (13).
Thymidine phosphorylase gene mutations in MNGIE, a human mitochondrial disorder.