Dihydropyrimidine dehydrogenase in normal and malignant endometrium: relationship with cell proliferation and thymidine phosphorylase

Relative level of thymidylate synthase mRNA expression in primary tumors and normal tissues predicts survival of patients with oral tongue squamous cell carcinoma

Thymidylate synthase (TS) is a major target of 5-fluorouracil (5-FU) and dihydropyrimidine dehydrogenase (DPD) is a rate-limiting enzyme in the degradation of 5-FU. There are no studies investigating the comparison of TS and DPD mRNA expressions in oral tongue SCC (OSCC) and nontumor tissues obtained from the same patients. In addition, increased interest has been focused on the biological roles of TS and DPD as the independent prognostic factors as well as responsive determinants for cancer patients with 5-FU based therapy. We determined the expression levels of TS and DPD in tumor (T) and nontumor squamous epithelial tissues (N) of OSCC using real-time reverse transcription-polymerase chain reaction and evaluated whether the T/N ratio would correlate with clinicopathological factors. The mRNA expressions of TS and DPD were significantly higher in tumor areas than in nontumor areas. No correlation was found between the T/N ratio of each mRNA expression and gender, clinical stage, T classification, N classification or differentiation. The T/N ratio of TS in patients that died of disease was significantly higher than in patients with free of disease, whereas there were no relationships between The T/N ratio of DPD and disease status. Clinical follow-up data showed shorter overall survival periods for cases with high T/N ratio of TS than for cases with low T/N ratio of TS with the statistically significant. Our study showed that TS but not DPD seems to have prognostic value in OSCC. These findings suggest that the assessment of TS activity may be useful both in the management and in the treatment of OSCC.

Regulation of human dihydropyrimidine dehydrogenase: implications in the pharmacogenetics of 5-FU-based chemotherapy

Dihydropyrimidine dehydrogenase is the enzyme that is critical for the efficacy and toxicity of the anticancer reagent 5-fluorouracil. It has been demonstrated that the regulation of the dihydropyrimidine dehydrogenase gene has an important role in the determination of the enzyme activity of dihydropyrimidine dehydrogenase. The regulation of the gene expression is thus discussed from two aspects: normal regulation by specificity proteins, and the epigenetic regulation by promoter methylation. The influence of the polymorphism on dihydropyrimidine dehydrogenase enzyme activity and other factors that have been suggested to be involved in dihydropyrimidine dehydrogenase regulation are also discussed.

Expression of thymidylate synthase and dihydropyrimidine dehydrogenase in oral squamous cell carcinoma: possible markers as predictors of clinical outcome

CONCLUSIONS

Our results suggest that assessment of dihydropyrimidine dehydrogenase (DPD) in oral squamous cell carcinoma (OSCC) may be a useful tool in evaluating clinical outcomes.

OBJECTIVE

The purpose of this study was to estimate the possibility of using thymidylate synthase (TS) and DPD as predictive values of clinical outcomes in OSCC.

MATERIALS AND METHODS

The expression of TS and DPD was examined by immunohistochemistry (IHC) and the real-time reverse transcription-polymerase chain reaction method in 23 patients with OSCC, and the association with clinicopathological factors was determined. Immunohistochemical expression of p53 and P-glycoprotein (P-gp) was also examined.

RESULTS

Neither TS protein nor TS mRNA expression showed any significant correlation to clinicopathological factors. In contrast, the patients with high DPD expression had significantly higher levels of recurrence compared with those with low DPD expression (p = 0.016). Similarly, six of seven patients with relapse had higher DPD mRNA expression values than the median value in the patients examined. On the other hand, no association was observed between TS or DPD and p53 or P-gp expressions.

Proteomic analysis of the proliferative and secretory phases of the human endometrium: Protein identification and differential protein expression

Proteomic analyses of the proliferative and secretory phases of the human endometrium were carried out to identify proteins and discover differentially expressed proteins using isotope-coded affinity tags, three stages of chromatographic separation and online tandem mass spectrometry (MS/MS). From an initial list of 346 proteins identified by ProICAT, manual inspection of MS/MS spectra and confirmatory searches pared the list down to 119 positively identified proteins. Only five of the proteins showed consistent differential expression. The utility of some of these proteins as indicators of true differential expression in the endometrium is open to discussion. The two proteins with unquestionable differential expressions in the secretory endometrium are: glutamate NMDA receptor subunit zeta 1 precursor and FRAT1. Some of the proteins that show no differential expression have previously been examined in gene-expression studies with similar conclusions.