Low Dihydropyrimidine Dehydrogenase Expression Research Articles

The Prognostic and Predictive Value of Dihydropyrimidine Dehydrogenase-Related Indicators in Clinical Outcomes of Chemotherapy in Colorectal Cancer Patients: a Systematic Review and Meta-Analysis.

Colorectal cancer (CRC) is the third most common cancer worldwide. Predictive biomarkers are needed to predict patients' outcomes and to select a chemotherapy regimen. We assessed whether dihydropyrimidine dehydrogenase (DPD)-related indicators can predict CRC patients' outcomes. We searched the studies in PubMed, EmBase, and the Cochrane Library up to March 4, 2018. We mainly analyzed different CRC patients' outcomes according to specific DPD-related indicators. Twenty-five articles were included in the meta-analysis. The results showed that for disease-free survival (DFS), low DPD expression was significantly superior to high expression (I2= 72%; HR: 1.59; 95%CI: 1.21-2.09; p= 0.001). However, this result had a potential publication bias (Begg's test: p= 0.007; Egger's test: p= 0.004). Among patients treated with chemotherapy, a high thymidylate phosphorylase (TP)/DPD ratio was advantageous for DFS (I2= 63.7%; HR: 0.65; 95%CI: 0.46-0.92; p= 0.015), and this result did not have a publication bias. For overall survival (OS), low DPD expression was superior to high expression (I2= 74.4%; HR: 2.11; 95%CI: 1.48-3.00; p< 0.001), although this result had a publication bias (Egger's test: p= 0.003; Begg's test: p= 0.010). There was no difference in OS according to the TP/DPD ratio (I2= 0%; HR: 0.92; 95%CI: 0.75-1.13; p= 0.420). DFS and OS were better in CRC patients with low DPD expression than in those with high DPD expression. However, because of publication bias, more DPD indicator-related studies, especially with negative results, are still needed. Patients with a high TP/DPD ratio have better DFS but not OS.

Dihydropyrimidine dehydrogenase predicts survival and response to interferon-\u03b1 in hepatocellular carcinoma

Metastasis and recurrence contribute to poor prognosis of hepatocellular carcinoma (HCC). Recently, we reported that interferon-α (IFN-α) can suppress metastasis of HCC; however, the underlying mechanism has not been fully described. In this study, we demonstrated that expression of dihydropyrimidine dehydrogenase (DPYD), a pyrimidine catabolic enzyme, was dose-dependently downregulated by IFN-α in HCC tissues from nude mice. Notably, DPYD expression was found to be significantly increased in HCC cell lines with higher metastatic potentials compared with their controls. Moreover, upregulation of DPYD in HCC cells could promote in vitro migration, invasion, and in vivo lung metastasis, and inducing changes characteristic of epithelial-mesenchymal transition (EMT). In contrast, knockdown of DPYD inhibited these processes. Mechanistically, DPYD functioned as a positive regulator of EMT in HCC by targeting the p38/NF-κB/Snail1 pathway. Clinically, tissue microarray analysis showed that high DPYD expression was positively associated with aggressive tumor characteristics, including larger tumor size, tumor recurrence, and advanced tumor node metastasis (TNM) stage, and independently correlated with poorer overall survival times after curative resection. HCC patients with low DPYD expression have better response to IFN-α therapy. Taken together, our findings elucidate that IFN-α could downregulate DPYD expression to inhibit EMT and HCC metastasis, and suggest that DPYD might be a potential prognostic biomarker and a therapeutic target for HCC.

The Impact of the Expression Level of Intratumoral Dihydropyrimidine Dehydrogenase on Chemotherapy Sensitivity and Survival of Patients in Gastric Cancer: A Meta-Analysis.

The potential impact that the intratumoral expression level of dihydropyrimidine dehydrogenase (DPD) has on chemotherapy sensitivity and long-term survival for gastric cancer (GC) patients remains controversial; therefore, this study seeks to clarify this issue. Our meta-analysis was performed using Review Manager (RevMan) 5.3 software. In vitro drug sensitivity tests, correlation coefficients between sensitivity to 5-fluorouracil (5-FU), and expression levels of intratumoral DPD were used as effective indexes to analyse. Overall survival (OS) and progression-free survival (PFS) were used as endpoints for patient outcome, and hazard ratios (HRs) and 95% confidence intervals (CIs) were noted as measures of effect. There were 15 eligible studies including 1805 patients for the final analysis. The analysis revealed a statistically significant difference between the expression level of intratumoral DPD activity, DPD mRNA levels, and sensitivity to 5-FU in GC patients, with high expression levels of intratumoral DPD resulting in low sensitivity to 5-FU. However, no matter what therapeutic regimens were used, there was no significant difference for patient outcomes between high and low DPD expression groups, either in OS or in PFS. In conclusion, high levels of intratumoral DPD expression have a negative impact on sensitivity to 5-FU in GC patients, but no prognostic value for long-term survival was uncovered.

Abstract 5028: Reverse translational research for identifying the correlation between EGFR mutation status and DPD protein expression in lung adenocarcinoma

Abstract [Background] Reverse translation research is often described as “From the Bedside to the Bench”, which means taking an understanding gained by observations in a patient population to create hypotheses and confirmation of the hypothesis in the laboratory. According to current chemotherapy treatment for lung adenocarcinoma, empirically, clinicians know that epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (EGFR-TKI) tend to be effective for radiological ground glass nodule- type lung adenocarcinomas. On the other hand, it has been shown that 5-FU sensitivity in patients with non-small cell lung cancer (NSCLC) is associated with EGFR mutation status. From such clinical hints, we identified a relationship between dihydropyrimidine dehydrogenase (DPD), a 5-FU degrading enzyme, and EGFR mutation status. [Methods] We firstly focused on clinicopathologic factors and in vitro correlations between DPD expression and EGFR mutation status. Secondly, we analyzed crosstalk between the EGFR signal cascade and DPD protein expression using EGFR mutated and not mutated cell lines. [Clinicopathological Study] EGFR mutations and messenger RNA (mRNA) levels of DPD were analyzed in 47 resected NSCLC tumors by laser-capture microdissection. EGFR mutation status and the immunohistochemical expression of DPD in 49 resected NSCLC tumors were also examined. As a result, adenocarcinoma in situ showed significantly higher DPD mRNA levels and more EGFR mutation frequency than other histological types (P &amp;lt; 0.05). DPD immunopositive cases were more frequently observed in adenocarcinoma, in females, and in nonsmokers; which were correlated with EGFR mutation status (P &amp;lt; 0.003). [Basic Study] In vitro, EGFR-mutated cell lines (PC9, HCC827; exon19 E746-A750 and H1975; exon21 L858R, T790M, gefitinib resistant) showed higher DPD mRNA and protein expression than wild types (H1437, H1299). The DPD gene (DPYD), and DPD protein expression were known to be regulated by the transcription factor Sp1. In the PC9 study, EGF treatment induced up-regulation of both Sp1 and DPD. Gefitinib, an EGFR-TKI, and mithramycin A, specific Sp-1 inhibitors, suppressed them. However, the phenomena were not observed in EGFR-wild types and EGFR-TKI resistant cell lines. These results suggest DPD is regulated mainly in EGFR signal cascade enhanced lung cancers such as EGFR mutated adenocarcinomas. 5-FU and its derivatives such as uracil-tegafur (UFT) or S-1 might be effective for EGFR wild type adenocarcinomas because of the low DPD expression. [Conclusion] Reverse translational research can provide useful information for clinical treatment. In the present study, we identified crosstalk between the EGFR signal cascade and DPD protein expression, which might affect therapeutic strategy for lung adenocarcinomas. Citation Format: Tomoshi Tsuchiya, Tetsuo Tominaga, Koji Mochinaga, Naoya Yamasaki, Keitaro Matsumoto, Takuro Miyazaki, Go Hatachi, Yuka Kitajima, Takeshi Nagayasu. Reverse translational research for identifying the correlation between EGFR mutation status and DPD protein expression in lung adenocarcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5028.

Abstract 1406: High expression of DPD and ALDH1 are associated with poor prognosis in pancreatic cancer

Abstract Background: Pancreatic cancer is a highly aggressive disease and currently the fourth leading cause for cancer related mortality. The annual incidence of it has been shown to be approximately equal to the annual death rate caused by it because of the propensity for early metastatic spread and because the disease is highly resistant to radiation and chemotherapy. Recently, cancer stem cells may play a crucial role in the development and progression of tumor. According to recent studies, cancer stem cell population in human pancreatic cancers are expressing the cell surface markers CD44+, c-Met, and ALDH1. 5-Fluorouracil (5-FU) is one of the key drugs and widely used in the treatment of pancreatic cancer. Dihydropyrimidine dehydrogenase (DPD) is the rate-limiting enzyme for 5-FU catabolism in liver, and it was reported that high DPD expression in cancer tissue was associated with 5-FU resistance and poor prognosis. The aim of this study is to examine if the pancreatic cancer stem cells express high DPD as a result acquiring chemoresistance to 5-FU. Methods: A total of 121 patients who underwent curative pancreatectomy for pancreatic cancer from April 2002 to December 2013 were analyzed. Immunohistochemical staining of DPD, ALDH1 and c-Met was performed using paraffin-embedded section of tissues. Expression of them were analyzed in interrelationship each other. Clinical relevance of those markers was confirmed with clinicopathological characteristics that were prospectively collected in our database. Results: Immunohistochemical analysis on clinical sample revealed that DPD expression was high in 55 (45.5%) patients, and high c-Met and ALDH1 expression were seen in 58 (47.9%) and 58 (47.9%) patients retrospectively. ALDH1 activity, DPD expression and sensitivity to 5-FU were examined using pancreatic cancer cell lines in vitro. High DPD expression was significantly associated with high ALDH1 expression not but c-Met, and associated with elderly patients (P = 0.0294) and overall survival (P = 0.0274). Pancreatic cell line with high DPD expression was more resistant to 5-FU than cells with low DPD expression in vitro. Low c-Met expression was significantly associated with high local infiltration (P = 0.0102). ALDH1 expression was significantly associated with relapse free survival (P = 0.0392) and overall survival (P = 0.0358). Conclusion: Our study demonstrated that high DPD expression was significantly associated with specific pancreatic cancer stem cell marker expression, may be involved in resistance to 5-FU treatment in pancreatic cancer. Citation Format: Kota Arima, Hirohisa Okabe, Daisuke Hashimoto, Takayoshi Kaida, Takaaki Higashi, Katsunobu Taki, Hideaki Takeyama, Hidetoshi Nitta, Hiromitsu Hayashi, Akira Chikamoto, Toru Beppu, Hideo Baba. High expression of DPD and ALDH1 are associated with poor prognosis in pancreatic cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1406. doi:10.1158/1538-7445.AM2015-1406

Somatic copy number changes in DPYD are associated with lower risk of recurrence in triple-negative breast cancers

Background:Genomic rearrangements at the fragile site FRA1E may disrupt the dihydropyrimidine dehydrogenase gene (DPYD) which is involved in 5-fluorouracil (5-FU) catabolism. In triple-negative breast cancer (TNBC), a subtype of breast cancer frequently deficient in DNA repair, we have investigated the susceptibility to acquire copy number variations (CNVs) in DPYD and evaluated their impact on standard adjuvant treatment.Methods:DPYD CNVs were analysed in 106 TNBC tumour specimens using multiplex ligation-dependent probe amplification (MLPA) analysis. Dihydropyrimidine dehydrogenase (DPD) expression was determined by immunohistochemistry in 146 tumour tissues.Results:In TNBC, we detected 43 (41%) tumour specimens with genomic deletions and/or duplications within DPYD which were associated with higher histological grade (P=0.006) and with rearrangements in the DNA repair gene BRCA1 (P=0.007). Immunohistochemical analysis revealed low, moderate and high DPD expression in 64%, 29% and 7% of all TNBCs, and in 40%, 53% and 7% of TNBCs with DPYD CNVs, respectively. Irrespective of DPD protein levels, the presence of CNVs was significantly related to longer time to progression in patients who had received 5-FU- and/or anthracycline-based polychemotherapy (hazard ratio=0.26 (95% CI: 0.07–0.91), log-rank P=0.023; adjusted for tumour stage: P=0.037).Conclusion:Genomic rearrangements in DPYD, rather than aberrant DPD protein levels, reflect a distinct tumour profile associated with prolonged time to progression upon first-line chemotherapy in TNBC.

A phase II study of modulated-capecitabine and docetaxel in chemonaive patients with advanced non-small cell lung cancer (NSCLC)

This phase II single-arm trial of docetaxel and capecitabine in previously untreated non-small cell lung cancer (NSCLC) patients was designed to evaluate response rate of this regimen based on promising efficacy data from phase II testing in pre-treated NSCLC patients. The trial also evaluated the correlation between peripheral blood dihydropyrimidine dehydrogenase (DPD) expression and efficacy/toxicity. Patients with advanced NSCLC (metastatic, including malignant pleural effusion) without prior chemotherapy were enrolled. Baseline DPD screening was performed; patients with baseline DPD level < 0.07 nmol/min/mg protein were considered ineligible for the study. Treatment included a 28-day cycle of docetaxel 36 mg/m(2) on days 1, 8, 15 and capecitabine 1250 mg/m(2)/day in divided doses on days 5-18. Overall response rate (RR) was the primary endpoint with a target RR of 50%. Correlative studies included evaluation of DPD activity levels in peripheral blood and correlation with clinical responses. Twenty-eight patients received 86 cycles of treatment (median 3 cycles) and were evaluable for response. The RR was 18% (5 patients); RR did not meet the pre-specified efficacy endpoint and the trial was stopped. 14 patients had stable disease (SD - 50%) and 4 patients had SD >12 weeks. Median time to progression was 3.3 months (95% CI 1.5-4.6 months). Median overall survival was 10.5 months (95% CI: 3.2-15 months). Main toxicities included fatigue, stomatitis and leukopenia. DPD levels ranged from 0.06 to 0.26 nmol/min/mg. The majority of responders (4/5) had DPD levels ≤0.1 nmol/min/mg. Most of the responders (4/5) experienced grade 3 toxicities including leukopenia, dehydration, fatigue, and diarrhea. None of the patients (0/4) with higher DPD levels (> 0.2 nmol/min/mg) had a response. The response rate for the regimen did not demonstrate sufficient activity and further study of this regimen in this setting is not indicated. Interestingly, the results suggest that low DPD expression may be associated with response to capecitabine but also with increased toxicity.

Role of thymidylate synthase and dihydropyrimidine dehydrogenase mRNA in intrahepatic cholangiocarcinoma

Thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) are important enzymes in the metabolism of 5-fluorouracil and possible predictive markers. We conducted this study to clarify if TS and DPD gene expressions are a prognostic indicator for intrahepatic cholangiocarcinoma (IHCC). The subjects of this study were 21 patients with IHCC who had undergone surgical resection. Intratumoral TS and DPD mRNA expressions were examined using the Danenberg tumor profile method and classified into two groups according to the median value of each. We then compared the clinicopathological variables, including prognosis, between the high and low expression groups. Low DPD expression was correlated with macroscopic type, namely, mass-forming + infiltrative (P = 0.08). Postoperative survival rates in the low DPD expression group were significantly lower than those in the high DPD expression group. Multivariate analysis revealed macroscopic type to be an independent prognostic factor, whereas TS mRNA expression did not correlate with any clinicopathological variables, including prognosis. Low DPD mRNA expression was related to macroscopic type and associated with poor prognosis. DPD mRNA expression in tumor cells is suggested to be an important regulator of malignant behavior in IHCC.

Prognostic impact of dihydropyrimidine dehydrogenase expression on pancreatic adenocarcinoma patients treated with S‐1‐based adjuvant chemotherapy after surgical resection

The aim of this study is to investigate the prognostic value of intratumoral expression of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), and orotate phosphoribosyltransferase (OPRT) in patients treated with S-1-based chemotherapy after surgical resection for pancreatic adenocarcinoma. Intratumoral TS, DPD, and OPRT expression was investigated in 106 patients with resected pancreatic adenocarcinoma by immunohistochemistry. Associations between clinicopathological factors, including intratumoral TS, DPD, and OPRT expression, and survival were evaluated by univariate and multivariate analyses. Of 106 patients, 72 had received S-1-based adjuvant chemotherapy (S-1(+) group), and 34 had not (S-1(-) group). High TS, DPD, and OPRT expression was observed in 64%, 37%, and 66% of patients, respectively. Among S-1(+) group patients, survival was significantly better for patients with low DPD expression than for patients with high DPD expression (P = 0.022). Intratumoral DPD expression was the only independent prognostic factor for patients treated with S-1-based adjuvant chemotherapy by multivariate analysis (P = 0.037). Intratumoral TS and OPRT expression did not appear to influence survival. Intratumoral DPD expression may be a relevant predictive marker of survival benefit associated with S-1-based adjuvant chemotherapy for pancreatic adenocarcinoma.

A retrospective study on TS mRNA expression and prediction of the effects of adjuvant oral 5-fluorouracil in breast cancer

Nucleic acid-metabolizing enzymes, such as thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), thymidine phosphorylase (TP) and orotate phosphoribosyl transferase (OPRT), have attracted attention as candidates for response determinants of 5-fluorouracil (5-FU). Whether the expression levels of these enzymes can be adopted as valuable parameters for 5-FU sensitivity in breast cancer has yet to be elucidated. In the present study, intratumoral mRNA expression of TS, DPD, TP and OPRT were determined in formalin-fixed paraffin-embedded surgical specimens collected from 217 breast cancer patients, using the Danenberg Tumor Profile method, which combines microdissection and real-time-polymerase chain reaction. The significance of these enzymes as prognostic and 5-FU efficacy-predicting factors was evaluated. Our data showed that a low DPD expression is related to a high nuclear grade and other factors including hormone receptor-negativity. Low expression levels of TP were found in hormone receptor-negative tumors. TS and OPRT expression were not related to various clinicopathological factors, but patients with a high TS mRNA expression showed a significantly poorer prognosis in cases where 5-FU was not administered. The efficacy of 5-FU was more significant when administered for more than 6 months in the group with a high TS mRNA expression. These data suggest that TS mRNA expression in breast cancer tissue is an ideal predictor of outcomes for patients with no administration of 5-FU, and of the efficacy of 5-FU.

Molecular determinants of efficacy for 5‐FU‐based treatments in advanced colorectal cancer: mRNA expression for 18 chemotherapy‐related genes

5-Fluorouracil (5-FU)-based regimens remain a cornerstone in the treatment of colorectal cancer (CRC). However, the attendant toxicity prevents these regimens from reaching maximum therapeutic potential. In this retrospective analysis, we examined the pretreatment expression of 18 genes in archival tumor bank samples from patients with advanced CRC to determine if one or more of the selected genes showed promise as either a prognostic or predictive marker of 5-FU-based treatment outcomes. One hundred and forty-four CRC patient samples (collected from 1983 to 2004) were analyzed via real-time PCR for gene expression. Univariate analyses were used to correlate gene expression with efficacy and time-to-event variables. Low thymidine phosphorylase (TP), dihydrofolate reductase, dihydropyrimidine dehydrogenase (DPD), excision repair cross-complementing 1 (ERCC1) and thymidylate synthase gene expression were associated with better time-to-progression in the entire population. Low TP, DPD and ERCC1 expression were independently associated with improved overall survival. Low TP gene expression was also predictive of response. This study suggests that TP gene expression in particular is a predictive as well as a prognostic biomarker for advanced CRC patients. Gene panels assessing pretreatment TP, DPD, ERCC1, dihydrofolate reductase and thymidylate synthase gene expression may help improve the therapeutic potential of 5-FU- or other novel antifolate-based regimens. Further analysis of the prognostic or predictive value of these genes in prospective trials in CRC patients seems warranted.

Prognostic significance of thymidylate synthase, dihydropyrimidine dehydrogenase and thymidine phosphorylase protein expression in colorectal cancer patients treated with or without 5-fluorouracil-based chemotherapy

BackgroundLow tumour expression levels of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD) and thymidine phosphorylase (TP) have been linked with improved outcome for colorectal cancer (CRC) patients treated with 5-fluorouracil (5-FU). It is unclear whether this occurs because such tumours have better prognosis or they are more sensitive to 5-FU treatment. Patients and methodsAssociations between TS, DPD and TP levels, determined by tissue microarrays and immunohistochemistry, and survival was evaluated in 945 CRC patients according to treatment status. ResultsLow TS and DPD expression associated with worse prognosis in stage II [hazard ratio (HR)=1.69, 95% confidence interval (CI) (1.09–2.63) and HR=1.92 (95% CI 1.23–2.94), respectively] and stage III CRC patients treated by surgery alone [HR=1.39 (95% CI 0.92–2.13) and HR=1.49 (95% CI 1.02–2.17), respectively]. Low TS, DPD and TP associated with trends for better outcome in stage III patients treated with 5-FU [HR=0.81 (95% CI 0.49–1.33), HR=0.70 (95% CI 0.42–1.15) and HR=0.66 (95% CI 0.39–1.12), respectively]. ConclusionLow TS and DPD expression are prognostic for worse outcome in CRC patients treated by surgery alone, whereas low TS, DPD and TP expression are prognostic for better outcome in patients treated with 5-FU chemotherapy. These results provide indirect evidence that low TS, DPD and TP protein expression are predictive of good response to 5-FU chemotherapy.

Dihydropyrimidine dehydrogenase and orotate phosphoribosyltransferase in esophageal cancer patients: Correlation with clinicopathological factors and prognosis

Thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD) and orotate phosphoribosyltransferase (OPRT) are fluoropyrimidine metabolic enzymes which play important roles in the response of cancer patients to chemotherapy. In esophageal cancer, little is known about the relationship between the expression of these enzymes and corresponding clinicopathological features. In the present study, TS, DPD and OPRT expression levels were evaluated in 72 resected esophageal cancer specimens using immunohistochemistry. The relationship between enzyme expression and clinicopathological features was assessed using Fisher's exact test or the χ2 test (categorical variables), or the Mann-Whitney rank-sum test (continuous variables). Survival curves were calculated using the Kaplan-Meier method, and differences evaluated using the log-rank test. The Cox proportional hazards model was also used. High DPD expression was associated with depth of invasion, nodal status, tumor stage, lymphatic invasion and venous invasion (P<0.001, P=0.004, P<0.001, P=0.006, P=0.038, respectively), as well as with decreased patient survival (P=0.007). In patients receiving adjuvant chemotherapy, low DPD expression did not significantly improve recurrence-free survival. OPRT was particularly expressed in esophageal cancer cells as compared to normal squamous cells. High OPRT expression was associated with depth of invasion and venous invasion (P=0.006, P=0.003, respectively). To conclude, in esophageal cancer DPD expression was associated with tumor progression and prognosis, and OPRT expression was correlated with carcinogenesis and tumor progression.

Predictive Role of Thymidylate Synthase, Dihydropyrimidine Dehydrogenase and Thymidine Phosphorylase Expression in Colorectal Cancer Patients Receiving Adjuvant 5-Fluorouracil

Objective: The combined assessment of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD) and thymidine phosphorylase (TP) gene expressions in metastatic colorectal cancer has been reported to be able to predict the efficacy of fluoropyrimidine-based chemotherapy. In order to evaluate the prognostic role in the adjuvant setting, we investigated the TS, DPD and TP expression in primary tumors of colorectal cancer patients treated with 5-fluorouracil (5-FU). Methods: TS, DPD and TP expression levels were determined by immunohistochemistry in paraffin-embedded primary tumor tissues from 62 patients with Dukes’ stage B and C colorectal cancers who underwent surgery and received adjuvant systemic chemotherapy with 5-FU. The median follow-up was 90 months (range 17–127). Results: Dukes’ stage C cancer and high TS expression were independent markers of poor prognosis for disease-free survival (DFS; p = 0.0009 and p = 0.007, respectively) and overall survival (OS; p = 0.0005 and p = 0.011, respectively). By multivariate analysis, patients with high DPD expression had significantly shorter DFS (p = 0.007) and OS (p = 0.005) compared to patients with low DPD expression. In the combined analysis of 2 markers, patients with low TS and low DPD had the best outcome in terms of DFS (p = 0.007) and OS (p = 0.03). The analysis of all 3 proteins showed that the patients with low expression of all 3 markers had significantly longer DFS (p = 0.04) and OS (p = 0.01) than patients with a high value of any one of the protein expressions. However, the joint analysis of 3 markers (group with TS–/DPD–/TP–) could not identify a subgroup of patients with a better prognosis compared to the analysis of 2 markers (group with TS–/DPD–). The analysis of Dukes’ stage C cancer patients confirmed a significant benefit in terms of DFS and OS (p = 0.001 and p = 0.006, respectively) when all 3 markers had low expression. We also found a positive significant correlation between TS and TP protein expression (p = 0.033). Conclusions: This retrospective investigation suggests that the combined assessment of TS and DPD may be useful to evaluate the prognosis of patients with Dukes’ B and C colon carcinoma receiving 5-FU adjuvant chemotherapy. The role of TP as a predictor for 5-FU-based therapy needs further investigations.

Expression of thymidylate synthase and dihydropyrimidine dehydrogenase in adenoid cystic carcinoma of the head and neck: Correlation with clinical outcome

The purpose of this study was to estimate the possibility of using thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), and p53 as predictive values of clinical outcome in adenoid cystic carcinoma (ACC). The expressions of TS, DPD, and p53 were examined with immunohistochemistry in 27 ACC patients, and the association with clinicopathological factors was determined. Cases with high DPD expression had significantly higher distant metastasis rates compared to those with low DPD expression (p=0.001), whereas neither TS nor p53 expression showed any significant correlation to clinicopathological factors. Interestingly, six of 14 early-stage patients had distant metastases and all of their tumors showed high DPD expression. Kaplan-Meier analysis revealed that a solid histological pattern and distant metastasis correlated with a poor prognosis. In early-stage patients, whose tumor was completely resected, those with high TS or DPD expression had a worse prognosis compared to those with low expression, but the difference did not reach statistical significance (TS, p=0.178; DPD, p=0.251). Our results suggest that assessment of DPD expression in ACC may be a useful tool in determining the mode of treatment as well as evaluating clinical outcome.

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.

Phase II study of tailored chemotherapy for advanced colorectal cancer with either 5-fluouracil and leucovorin or oxaliplatin and irinotecan based on the expression of thymidylate synthase and dihydropyrimidine dehydrogenase

Background: Thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) are essential enzymes for 5-fluorouracil (5-FU) metabolism. In patients with advanced colorectal cancer (ACRC), retrospective studies have shown that low expression levels of TS and DPD correlated with response to 5-FU. We performed a prospective study in which the choice of first-line chemotherapy with either 5-FU or a non-5-FU containing regimen was based on TS and DPD expression.Patients and methods: Fresh-frozen samples of metastases were obtained from 58 previously untreated patients with ACRC. mRNA expression of TS and DPD was quantified using an RT–PCR assay. Patients with low tumor expression of both TS and DPD received weekly bolus 5-FU/leucovorin (LV) 500mg/m2 (group A); patients with high TS and/or DPD received 3-weekly oxaliplatin 85mg/m2 and irinotecan 200mg/m2 (group B). After progression, cross-over to the alternative regimen was attempted.Results: Of 53 eligible patients, 31 had tumors with both low TS and low DPD, and were treated in group A. A response was observed in 11 patients [35%; 95% confidence interval (CI) 19% to 54%]. Cross-over to second-line oxaliplatin/irinotecan resulted in a partial response in two out of 16 patients (13%; 95% CI 1% to 38%). In group B, four out of 22 patients responded (18%; 95% CI 5% to 40%), while no responses were observed in 12 patients after cross-over to 5-FU/LV (0%; 95% CI 0% to 28%).Conclusions: Prospective selection of 5-FU/LV chemotherapy based on low TS and DPD expression in patients with ACRC did not confirm the high response rates reported in retrospective studies. The procedure of obtaining metastatic tissue and quantitation of enzymes appeared feasible but cumbersome. Before assessing the clinical utility of a predictive marker in a randomized trial, future studies should focus on prospective validation of the assay in a large and well defined population.

Recurrence and 5-FU sensitivity of stage III/Dukes' C colorectal cancer with occult neoplastic cells in lymph node sinuses

In 103 patients without occult neoplastic cells (ONCs) in the lymph node sinuses, the 5-year relapse-free survival (RFS) rate and overall survival (OS) rate were 90.2% and 91.8%, respectively. In 21 patients with ONCs, the 5-year RFS and OS rates were 34.9% and 62.3%, respectively. There were marked differences of survival between the two groups (p=0.0000 and p=0.0003). In the primary tumors of the 21 ONC-positive patients, high and low TS levels were found in 46.2% (6/13) and 53.8% (7/13) of the recurrence group (n=13), respectively. High and low DPD levels were found in 23.1% (3/13) and 76.9% (10/13), respectively. In the non-recurrence group (n=8), high and low TS or DPD levels were found in 75.0% (6/8) and 25.0% (2/8) versus 12.5% (1/8) and 87.5% (7/8), respectively. The percentage of patients with high TS and low DPD levels was 23.1% (3/13) in the recurrence group and 62.5% (5/8) in the non-recurrence group (p=0.07). These results suggest that the presence of ONCs had a clear association with the 5-year RFS and OS rates. The recurrence group of ONC-positive patients with stage II/Dukes' B colorectal cancer was unlikely to be highly responsive to 5-FU-based treatment, thus requiring multi-combination chemotherapy using CPT-11 and/or L-OHP.

Tumor dihydropyrimidine dehydrogenase expression is a useful marker in adjuvant therapy with oral fluoropyrimidines after curative resection of colorectal cancer.

Dihydropyrimidine dehydrogenase (DPD) is the rate-limiting enzyme of 5-fluoropyrimidine (5-FU) catabolism. We examined whether tumor DPD expression is an effective marker in adjuvant therapy with oral fluoropyrimidines after curative resection of colorectal cancer. We studied 89 patients with stage II-III colorectal cancers who had undergone curative resections and received oral 5-FU-based adjuvant chemotherapy. The levels of DPD expression in tumor and normal colonic mucosa were measured by an enzyme-linked immunosorbent assay. In 53 tumor samples, DPD enzymatic activity was also analyzed in order to evaluate the relationship between DPD expression and enzymatic activity. DPD expression significantly correlated with DPD enzymatic activity in these 53 tumors ( r=0.56; P<0.001). DPD expression in the tumors was significantly lower than in normal mucosa (47.1+/-30.8 and 56.4+/-18.5 U/mg protein, respectively; P<0.05). We designated the cut-off value of tumor DPD as its median value (46.0 U/mg protein). Patients with low DPD expression had longer disease-free intervals than those with high DPD expression according to univariate analysis ( P=0.026). In a multivariate analysis, low DPD expression was significantly and independently associated with better survival. Tumor DPD expression is a useful marker for use with adjuvant chemotherapy with oral fluoropyrimidines after curative resection of colorectal cancer.

Clinical significance of thymidine phosphorylase and dihydropyrimidine dehydrogenase expression in transitional cell cancer.

Thymidine phosphorylase (TdR-Pase) and dihydropyrimidine dehydrogenase (DPD) are thought to be key enzymes in the metabolic pathways of 5-fluorouracil (5-FU). Theoretically, tumors which have low DPD and/or high TdR-Pase expression should be 5-FU-sensitive. TdR-Pase also has angiogenic expression which aids tumor progression and metastasis. However, little is known concerning the relationship between DPD expression and clinical malignant potential, especially in urological cancer. Transitional cell cancer (TCC) tissues were obtained from 50 patients, and TdR-Pase and DPD expression was measured by ELISA and radioenzyme assay, respectively. The sensitivity of 23 of the 50 specimens to 5-FU was assessed in a histoculture drug response assay (HDRA), an in vitro chemosensitivity test. TdR-Pase and DPD expression in TCC tissues was higher than in normal urothelial tissues. The expression of both TdR-Pase and DPD in TCC increased with histological grade and stage. Superficial bladder cancer patients who had undergone transurethral resection were divided into two groups, a recurrent and a nonrecurrent group. The expression of TdR-Pase and DPD was higher in the recurrent group than in the nonrecurrent group, but the differences were not significant. There was a significant inverse correlation between DPD expression and 5-FU sensitivity. However, TdR-Pase exhibited no correlation with 5-FU sensitivity. The expressions of both enzymes may be a good indicator of the malignant potential of TCC. Although DPD may be a good indicator of sensitivity of TCC to 5-FU, TdR-Pase appeared not to regulate the sensitivity of TCC to 5-FU.