DPD Expression Research Articles

Synergistic antitumor effects of FGFR2 inhibitor with 5‐fluorouracil on scirrhous gastric carcinoma

Scirrhous gastric carcinoma (SGC) carries the highest mortality because of a frequent metastasis to lymph node (LN). S1, a 5-fluorouracil (5-FU) analog, is clinically available for gastric cancer at an advanced stage. Fibroblast growth factor receptor 2 (FGFR2) is required for the proliferation of SGC. The objective of this study is to clarify the benefit of a combination of S1 and kinase inhibitors including FGFR2 inhibitor Ki23057 in gastric cancer. OCUM-2MLN and KATO-III were derived from SGC. MKN-7 and MKN-74 were derived from non-SGC. MTT assay was used to examine the growth-inhibitory activity of 5 small-synthetic molecules including Ki23057, Sunitinib, Glivec, Lapatinib or SU11274, in cells cultured with 5-FU. Combination effects of 5-FU with Ki23057 on proliferation, apoptosis and mRNA expression were examined. S1 and/or Ki23057 were administered to murine models of SGC created by the orthotopic inoculation of OCUM-2MLN cells. Ki23057 at 100 nM significantly (p < 0.01) inhibited the proliferation and decreased the phosphorylation of FGFR2 in SGC cells, but not in non-SGC. Ki23057 showed synergistic antitumor effects for SGC cells in combination with 5-FU using CalcuSyn analysis, but Sunitinib, Glivec, Lapatinib and SU11274 did not. The combination of Ki23057 and 5-FU decreased DPD expression and increased apoptosis rates and p21 expression level of SGC cells. The combined administration of S1 and Ki23057 significantly (p < 0.05) decreased orthotopic tumors as well as LN metastasis more effectively than S1 alone. These findings suggested that the combined treatment with 5-FU and Ki23057 produced synergistic antitumor effects and is therapeutically promising for SGC treatment.

Dihydropyrimidine dehydrogenase mRNA expression in peripheral blood of rectal cancer patients is significantly associated with residual tumor and distant metastases following resection

DPD and TS expression have been shown to correlate with response of 5-FU based chemotherapy in colorectal cancer tissue. Little is known about mRNA expression levels of TS and DPD in peripheral blood. The goals of this study were to test the feasibility of DPD and TS detection in blood and their associations to TNM staging and complete surgical resection. Whole blood was drawn 1 day pre- and 10 days post-operatively from 23 patients with rectal cancer. Either adjuvant (n = 15) or neoadjuvant (n = 8) treatment was performed. Tumor cells were enriched from whole blood by density gradient centrifugation prior to extraction of total cellular RNA and subsequent direct quantitative reverse transcriptase-PCR assays. DPD was detectable in 21/23 patients (91.3%) and TS in 14/23 (61.7%). Stepwise multiple linear regression models showed a significant association of DPD expression with distant metastases (P = 0.004) and residual tumor categories (P = 0.03). Quantitative analysis of TS and DPD mRNA expression in peripheral blood of rectal cancer patients is technically feasible. DPD expression levels appear to be associated with residual tumor categories and might serve as a molecular marker for complete tumor resection. Larger studies seem to be warranted to scrutinize our hypothesis.

Candidate mechanisms for capecitabine‐related hand–foot syndrome

The oral fluoropyrimidine prodrug capecitabine is widely used in oncology. Capecitabine was designed to generate 5FU via the thymidine phosphorylase (TP) enzyme, preferentially expressed in tumoral tissues. Hand-foot syndrome (HFS) is a limiting toxicity of capecitabine. A pilot study on healthy volunteers was conducted in order to test the hypothesis that the occurrence of HFS could be related to tissue-specific expression of drug-metabolizing enzymes in the skin of the palm and sole. To this end, the expression of TP (activating pathway), dihydropyrimidine dehydrogenase (DPD, catabolic pathway) and cell proliferation (Ki67) were measured in the skin of the palm (target tissue for HFS) and of the lower back (control area). Two paired 4-mm diameter punch biopsy specimens (palm and back) were taken in 12 healthy volunteers. Immunohistochemical analyses were performed on frozen tissues. Proliferation rate (Ki67 staining) was significantly higher in epidermal basal cells of the palm compared with the back (P = 0.008). Also, TP and DPD expression were significantly greater in the palm relative to the back (P = 0.039 and 0.012, respectively). TP and Ki67 expression were positively and significantly correlated in the palm. The high proliferation rate of epidermal basal cells in the palm could make them more sensitive to the local action of cytotoxic drugs. TP-facilitated local production of 5FU in the palm during capecitabine treatment could explain the occurrence of HFS. This observation may support future strategies to limit the occurrence of HFS during capecitabine therapy.

Alteration of dihydropyrimidine dehydrogenase expression by IFN-α affects the antiproliferative effects of 5-fluorouracil in human hepatocellular carcinoma cells

Dihydropyrimidine dehydrogenase (DPD) is the rate-limiting enzyme in the catabolism of 5-fluorouracil (5-FU) and its activity is closely associated with cellular sensitivity to 5-FU. This study examines the role of DPD in the antiproliferative effects of 5-FU combined with IFN-alpha on hepatocellular carcinoma (HCC) cells in culture and asks whether IFN-alpha could affect DPD expression. The combined action of IFN-alpha and 5-FU on three HCC lines was quantified by a combination index method. Coadministration of IFN-alpha and 5-FU showed synergistic effects against HAK-1A and KYN-2 but antagonistic effects against KYN-3. The cellular expression levels of DPD mRNA and protein were markedly up-regulated in KYN-3 cells by IFN-alpha but were down-regulated in HAK-1A and KYN-2. The expression of thymidylate synthase mRNA and protein was down-regulated by IFN-alpha in all three cell lines. Coadministration of a selective DPD inhibitor, 5-chloro-2,4-dihydroxypyridine (CDHP), enhanced the antiproliferative effect of 5-FU and IFN-alpha on KYN-3 approximately 4-fold. However, the synergistic effects of 5-FU and IFN-alpha on HAK-1A and KYN-2 were not affected by CDHP. The antiproliferative effect of 5-FU could thus be modulated by IFN-alpha, possibly through DPD expression, in HCC cells. Inhibition of DPD activity by CDHP may enhance the efficacy of IFN-alpha and 5-FU combination therapy in patients with HCC showing resistance to this therapy.

Hand-foot syndrome (HFS) in patients receiving capecitabine: A pharmacological explanation

2019 Background: Use of the oral fluoropyrimidine capecitabine, which generates 5FU in tumor tissues, is currently expanding. HFS is frequently associated with administration of capecitabine. However, the underlying pharmacological mechanism of HFS is still not elucidated. In a previous experimental study, we ruled out a possible implication of 5FU catabolites (FUH2 and FBAL) in the etiology of HFS (Anti-Cancer Drugs 15: 969, 2004). The aim of this study was to investigate expression levels of thymidine phosphorylase (TP, the main activating enzyme of capecitabine) and dihydropyrimidine dehydrogenase (DPD, the rate-limiting enzyme of 5FU catabolism) in skin samples from the palm area of the hand (target zone) and from the back (control zone). Methods: Paired-skin biopsies have been planned in 12 healthy volunteers, in agreement with the local ethical committee. Expressions of TP, DPD, and Ki67 (cell proliferation marker) were analyzed by a two-step immunohistochemical method using specific monoclonal antibodies (from Calbiochem for TP, Roche for DPD and Dako for Ki67) and immunoperoxydase revelation (kit ABC Vectastain). Results: Data from the first four subjects indicate no significant difference in the strong Ki67 staining between control and target zones. TP was markedly expressed in the basal layer of the epidermis (BLE), with similar staining in control and target zones. Interestingly, in 3 cases out of 4, DPD was strongly expressed (2+, 3+) in the BLE of the control zone and much less (0, 1+) in the paired-target zone. Definitive data on 12 subjects will be presented. Conclusions: This preliminary original observation suggests that capecitabine may be locally activated in the skin due to high TP expression. The relative absence of DPD expression in the palm area may explain the specificity of HFS, which may result from a lack of local 5FU catabolism. These new data open the way to a possible pharmacological approach to limit HFS. No significant financial relationships to disclose.

Long-term survival and tumor 5-FU sensitivity in patients with stage IV colorectal cancer and peritoneal dissemination

Among 125 patients with peritoneal dissemination (P1-3) of colorectal cancer, including those with other synchronous metastases, the 5-year overall survival (OS) rate was 13.3% for P1 patients (n=30), 12.8% for P2 patients (n=39), and 1.8% for P3 patients (n=56) (P1 vs. P2, p=N.S.; P2 vs. P3, p=0.02; P1 vs. P3, p=0.001), while the median survival time (MST) was 12.0, 14.1, and 3.1 months, respectively. The 5-year OS rates for patients who had peritoneal dissemination without other metastases were 17.6% (n=17), 12.5% (n=19), and 3.4% (n=28) (P1 vs. P2, p=N.S.; P2 vs. P3, p=N.S.; P1 vs. P3, p=0.039), while the MST was 25.1, 15.1, and 12.5 months, respectively. In the P3 short survival group (SSG; n=13), TS expression was high in 7.7% (1/13) and low in 92.3% (12/13) of tumors, while DPD expression was high in 38.5% (5/13) and low in 61.5% (8/13) of tumors. In the P3 long survival group (LSG; n=15), the corresponding values were 80.0% (12/15), 20.0% (3/15), 33.3% (5/15), and 66.7% (10/15). High TS and low DPD expression was found in only 7.7% (1/13) of the SSG tumors vs. 46.7% (7/15) of the LSG tumors (p=0.028). These results suggest that the prognosis of stage IV colorectal cancer with P3 peritoneal dissemination is extremely poor. In addition, patients fitting the SSG criteria are unlikely to respond to treatment with 5-FU+LV, and may need combination chemotherapy using CPT-11 and/or L-OHP.

Recurrence and 5-FU sensitivity of stage I/II node-negative breast, lung, or gastric cancer with occult neoplastic cells in lymph node sinuses

This study was designed to examine the relationship between the presence of occult neoplastic cells (ONCs) in lymph nodes (LNs) and survival in 238 patients with stage I/II LN-negative cancer of the breast, lung, or stomach. In addition, immunohistochemistry for TS and DPD was used to compare the 5-FU sensitivity of the primary tumor in ONC (+) patients. The 5-year relapse-free survival (RFS) rate of 215 ONC (-) patients and 23 ONC (+) patients was 95.2 and 82.6%, respectively (p=0.0107). The 5-year overall survival (OS) rate of the ONC (-) and (+) patients was 97.4 and 77.4%, respectively (p=0.0000). The 6 ONC (+) patients with recurrence showed high and low TS expression in 33.3% (2/6) and 66.7% (4/6), respectively, while high and low DPD expression was observed in 16.7% (1/6) and 83.3% (5/6), respectively. In the 17 ONC (+) patients without recurrence, the corresponding values were 64.7% (11/17), 35.3% (6/17), 29.4% (5/17), and 70.6% (12/17). Patients with a combination of high TS and low DPD expression accounted for 33.3% (2/6) of the ONC (+) patients with recurrence and 52.9% (9/17) of those without recurrence, showing no significant difference between the two groups. These results suggest that ONCs are associated with a lower survival rate and that ONC (+) patients are unlikely to respond to 5-FU+LV therapy.

Recurrence and 5-FU sensitivity of stage II/III node-positive gastric cancer with occult neoplastic cells in lymph node sinuses

The 5-year overall survival (OS) rates for patients without occult neoplastic cells (ONCs) were 43.0% in stage II (n=15), 52.2% in stage III (n=23), and 48.5% for stages II and III combined (n=38). For ONC-positive patients, the 5-year OS rates were 44.4% in stage II (n=7; p=0.88322), 11.3% in stage III (n=30; p=0.0006), and 17.5% for stages II and III combined (n=37; p=0.0019). Among the ONC(+) recurrence group (75.7%, 28/37), 42.9% (12/28) showed high TS expression in metastatic lymph nodes and 57.1% (16/28) showed low TS expression. In the case of DPD expression, 32.1% (9/28) showed high expression and 67.9% (19/28) showed low expression. Among the ONC(+) non-recurrence group (24.3%, 9/37), 66.7% (6/9) showed high TS expression and 33.3% (3/9) showed low TS expression, while high and low DPD expression was seen in 22.2% (2/9) and 77.8% (7/9), respectively. A combination of high TS and low DPD expression was found in 32.1% (9/28) of the recurrence group vs. 66.7% (6/9) of the non-recurrence group (p=0.070). These results suggest that ONCs are associated with OS. Unlike the non-recurrence group, the ONC(+) patients with recurrence of stage II/III node-positive gastric cancer are unlikely to respond to treatment with 5-FU + LV and may need combination chemotherapy based on L-OHP and/or CPT-11.

Combined GADD45A and Thymidine Phosphorylase Expression Levels Predict Response and Survival of Neoadjuvant-Treated Gastric Cancer Patients

We evaluated the expression of seven therapy-related genes to predict the clinical outcome of advanced gastric cancer patients treated with a neoadjuvant chemotherapeutic protocol. Pretherapeutic, formalin-fixed, and paraffin-embedded biopsies of 61 patients, who received a 5-fluorouracil (5-FU)- and cisplatin-based chemotherapy were studied. The expressions of the 5-FU-related genes TS, DPD, and TP and of the cisplatin-related genes ERCC1, ERCC4, KU80, and GADD45A were analyzed by quantitative real-time PCR. The expression levels of single genes and of various combinations were tested for an association with response and overall survival. High DPD levels were more frequently found in nonresponding patients and were associated with worse survival. GADD45A and TP levels showed weak associations with response, but GADD45A expression correlated with survival. There was no association with response for TS expression, but tumors with a high TS level were associated with worse survival. The combination of GADD45A and TP revealed the strongest predictive effect. High expression values of TP and/or GADD45A were exclusively found in nonresponding patients (P = 0.002) and were associated with a significantly poorer survival (P = 0.04). Combined gene expression levels of TP and GADD45A represent a new variable to predict the clinical outcome after neoadjuvant chemotherapy in gastric cancer. The association of DPD expression with response and survival underlines a predominant role of DPD to predict 5-FU sensitivity. The association of TS expression levels with survival but not with response suggests an importance of this gene for tumor progression.

Downregulation of TS, DPD, ERCC1, GST-Pi, EGFR, and HER2 gene expression after neoadjuvant three-modality treatment in patients with esophageal cancer

To find out if neoadjuvant therapy could alter tumor response determinants that might affect tumor sensitivity to the treatment, we investigated intratumoral expressions of genes associated with chemosensitivity, radiosensitivity, or both before and after radiochemotherapy. Twenty-four patients with locally advanced, resectable esophageal cancer (cT2-4,Nx,M0) received neoadjuvant 5-FU/cisplatin/36 Gy treatment followed by transthoracic en bloc esophagectomy. Expression levels of thymidylate synthase, dihydropyrimidine dehydrogenase, excision repair cross-complementing gene 1 , glutathione S-transferase Pi, epidermal growth factor receptor, and HER2 were measured in matched preradiochemotherapy endoscopic tumor biopsies and in postradiochemotherapy resection specimens. mRNA was isolated from formalin-fixed, paraffin-embedded, laser microdissected tumor tissues, and a quantitative fluorescent dye real-time reverse transcription polymerase chain reaction system was used for gene expression measurement. There was a significant reduction in the expression levels of thymidylate synthase (p < 0.01), dihydropyrimidine dehydrogenase (p = 0.03), excision repair cross-complementing gene 1 (p < 0.01), glutathione S-transferase Pi (p = 0.03), HER2 (p < 0.01), and epidermal growth factor receptor (p = 0.04). The change in the levels of epidermal growth factor receptor mRNA in post- compared with pretreatment specimens was significantly associated with the histopathologic grade of regression (p = 0.01). The expression levels of a set of genes that are possible determinants of 5-FU/cisplatin/radiation therapy antitumor activity are significantly downregulated by neoadjuvant radiochemotherapy in esophageal cancer.

Evaluation of TS-1 based treatment and expression of thymidylate synthase and dihydropyrimidine dehydrogenase on oral squamous cell carcinoma

Seventeen oral squamous cell carcinoma (SCC) patients underwent chemotherapy with TS-1 (8 males and 9 females, mean age; 75.1 years, range; 47-102 years). TS-1 permitted five cases of oral chemotherapy on an outpatient basis and 8 cases in elder patients over 80-years of age. Excepting five patients who underwent TS-1 therapy as post-operative adjuvant chemotherapy, the therapeutic efficacy of TS-1 in 12 patients with or without irradiation, surgery or chemotherapy resulted in 3 cases of complete response (CR), 6 cases of partial response (PR), 3 cases of stable disease (SD), with no progressive disease (PD) cases (overall response rate; 75%). SCC samples obtained from biopsy were immunohistochemically stained with anti-TS and DPD polyclonal antibody. Although the statistical significance was not clear, the expression of TS and DPD for CR cases was lower than that for SD cases. TS-1 therapy improved quality of life (QOL) especially in elder patients with oral SCC, and our immunohistochemical results suggested the predictive possibilities of TS and DPD expression in response to TS-1.

Intratumoral DPD gene expression has a clinical significance in pancreatic adenocarcinoma (PAC) patients treated with S-1

4113 Background: Although the prognosis in patients with pancreatic adenocarcinoma (PAC) has been poor, we recently reported unusually high response rate and survival benefit of S-1 treatment in patients with PAC (Proc ASCO, #1042 2003). The aim of this study was to reveal genetic background of this unique activity of S-1 against PAC. S-1 is a novel oral fluoropyrimidine derivative consisting of Tegafur (FT) and DPD inhibitor (5-chloro-2, 4-dihydroxypyridine; CDHP). Accordingly intratumoral DPD mRNA expression level was measured to reveal whether the level was differenct from other GI cancer and whether it was relevant to chemosensitivity in PAC. Patients & Methods: Among 28 recurrent PAC patients treated with S-1, we obtained 15 responders and 13 non-responders. The mRNA was extracted from paraffin-embedded surgical specimens using laser captured microdissection, and relative expression levels of each DPD/β-actin were measured using a quantitative reverse transcription polymerase chain reaction (RT-PCR) (Taqman“) system. 30 colorectal cancer (CRC) patients treated with S-1 were enrolled as a control group. Results: Intrarumoral DPD mRNA expression level was significantly higher in PAC than that in CRC (P<0.0001: median expression; 1.38 / 0.56). DPD expression among responded PAC was significantly lower than non-responded PAC. (P= 0.012, Mann-Whitney U test). Conclusions: Intratumoral DPD mRNA expression level in PAC was relatively high, and the unique and intense S-1 activity against PAC could be resulted from compounded DPD inhibitor. And DPD gene expression was supposed to be a reliable factor for chemosensitivity with S-1 in PAC. No significant financial relationships to disclose.

Up-regulation of thymidine phosphorylase (TP) by radiotherapy (RT): a phase I study of capecitabine (CAP) with concurrent RT for pts with locally advanced (LA) pancreatic cancer (Pan Ca)

4104 Introduction: Concurrent 5-FU-RT is the standard Rx for LA Pan Ca. CAP is metabolized by TP to its metabolite, 5-FU. Preclinical studies suggest that RT prior to CAP leads to synergistic cytotoxicity and better antitumor effects than 5-FU-RT due to up-regulation of TP. Objective: This is a hypothesis-driven phase I study which examines the effect of RT on TP and TNF-alpha expression, defines MTD of CAP with RT and determines if there is a correlation between pt response and intra-tumor TP/DPD ratio. Patients and Methods: During Part A (CAP-RT) pts received concurrent RT (50.4 Gy) with escalating doses of CAP (600mg/m2 PO BID; 800mg/m2 PO BID; 1000mg/m2 PO BID) on days 1–5, 8–12, 15–19, 22–26, 29–33, and 36–40 in consecutive cohorts of 3–6 pts till MTD is achieved. After finishing Part A, pts were assessed for tumor response and resectability. During Part B (CAP), stable, responding and resected pts were treated with CAP 1000mg/m2 PO BID for 14d q 3 wks until disease progression. Re-staging asessment was performed q 3 cycles. Tumor specimens procured by EUS pre- and post-therapy (wk 2) were evaluated for TP, TNF-alpha and DPD mRNA levels by RT-Q-PCR. Results: From April to Dec 2003, 11 pts (4M/ 7F; Median age: 63 yrs; PS ECOG: 0–2) were enrolled. Toxicities are summarized in Table 1. DLT [Grade 3 diarrhea] was observed at 1000mg/m2 BID, and a total of 6 pts will be enrolled at this level to define MTD and DLT. No occurrence of Hand-Foot syndrome (HFS) was seen during Part A, and Grade 2 HFS was observed in 2 pts during Part B. With 5 pts still on study, 24 cycles have been administered, with a median of 3. Three pts responded to Rx (2 PR: 54% and 43%; 1 SD; 1 PD; 3 off-study due to delay > 2 wks). Intra-tumor expression of TP, TNF-alpha, and DPD are pending and will be available at the meeting. Conclusions: CAP-RT appears to be well tolerated and active in LA Pan Ca. Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Roche Roche; Sanofi Roche Pharmaceuticals

COX-2 status is a significant factor to predict a postoperative survival as well as an efficacy of postoperative adjuvant therapy in non-small cell lung cancer

9556 Background: Clinical significance of biomarkers in non-small cell lung cancer (NSCLC) remains unclear, and an exact and quantitative evaluation of biomarkers may be required to clarify the clinical significance. Methods: A total of 110 patients (pts) with completely resected p-stage I NSCLC were reviewed. RNAs were isolated from laser-captured tumor cells, and gene expression of VEGF, COX-2, MMP-2, MMP-9, EGFR, p27, TS, DPD, TP, and OPRT was quantitatively evaluated by a real-time RT-PCR assay. Results: COX-2 gene expression status was the only significant prognostic factor (Table), and a multivariate analysis confirmed that high COX-2 gene expression was an independent factor to predict a poor prognosis (p=0.005, RR=3.848 [95% CI, 1.500–9.874]). COX-2 gene expression status also predicted the efficacy of postoperative adjuvant chemotherapy using UFT (an oral 5-FU derivative); UFT administration was effective for low COX-2 gene-expression tumor (5-year survival rate, 93% for UFT-treated pts and 67% for surgery-alone pts; p=0.045), and was not effective for high COX-2 gene-expression tumor (5-year survival rate, 64% for UFT-treated pts and 62% for surgery-alone pts; p=0.677). COX-2 protein-expression status determined immunohistochemically was well correlated with COX-2 gene-expression status (p=0.001). However, COX-2 protein-expression status was not a significant prognostic factor nor a significant predictive factor of UFT administration. Conclusions: High COX-2 gene-expression in tumor cells was a significant factor to predict not only a poor prognosis but also an inefficacy of postoperative adjuvant chemotherapy for resected NSCLC. No significant financial relationships to disclose.

DPD mutations and expression in patients with serious toxicity during therapy with 5FU based regimens: National project

3118 Background: DPD is the key enzyme of the 5FU catabolism. Patients with the low DPD activity due to the mutation or low expression are highly threatened by the severe toxicity, when treated wit...

DPD mutations and expression in patients with serious toxicity during therapy with 5FU based regimens: National project

DPD mutations and expression in patients with serious toxicity during therapy with 5FU based regimens: National project

Updated results of an exploratory gene expression analysis for primary esophageal cancer (PEC) patients (pts) treated with oxaliplatin (OXP), protracted infusion (PI) 5FU and radiation (XRT)

4014 Background: In a study designed to explore the relationship between expression of TS, γGCS, γGT, ERCC-1 and XPA genes and clinical outcome for 38 pts with PEC, who received OXP (85 mg/m2 day (D)1, D15 and D29), PI 5FU (180 mg/m2 D8-D42 ) and XRT (5040 cGy beginning D8 for 28 fractions) TS appeared to be prognostic for survival (Leichman et al., Proc. ASCO, 22:263, 2003). Because recurrence and deaths have continued, an updated analysis for pts followed through October 2003 is presented including expression of DPD and MRP-2 genes. Methods: Pts had endoscopic biopsies of PEC prior to OXP (D1), prior to 5FU and XRT (D8) and at the end of treatment (ET). Gene expression was assayed typically in 2 specimens at each time point in 29 (ET) to 37 (D1) pts by real time QRT-PCR and expressed relative to β-actin. The mean mRNA levels at each time were logarithmically transformed and using Cox proportional hazards model with time-dependent covariates explored for relationships to survival (S) and progression free survival (PFS). Results: Overall median S (n=38) and PFS (n=38) are 26.9 and 12.1 months (mo) respectively at a median follow-up of 31 and 30 mo for the censored pts. Stage 4 (n=22) versus Stages 2/3 (n=16) showed no differences in S (90% C.I. on hazard ratio: 0.9, 3.8) or PFS (90% C.I. on hazard ratio: 0.9, 3.2). Now, a year after our initial analysis, only D1 mean XPA expression showed relation to S in a model that included stage (XPA 90% C.I. on hazard ratio: 1.3, 6.9). XPA as a time-dependent covariate at D1, D8 and ET for 28 pts with stage included also showed a relation to S (90% C.I. on hazard ratio: 1.0, 7.5). None of the biomarkers on D1 or as time-dependent covariates showed a relation to PFS. Conclusions: In successive exploratory analyses of PEC pts treated with OXP, 5FU and XRT, TS and XPA, gene expressions demonstrated variable time dependent relationships to survival. Expression of these genes, and their association with survival for PEC pts undergoing multimodality are appropriate for further larger studies. (Supported by CA 915490 and CA 16056) Author Disclosure Employment or Leadership Consultant or Advisory Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Sanofi-Synthalabo

Updated results of an exploratory gene expression analysis for primary esophageal cancer (PEC) patients (pts) treated with oxaliplatin (OXP), protracted infusion (PI) 5FU and radiation (XRT)

4014 Background: In a study designed to explore the relationship between expression of TS, γGCS, γGT, ERCC-1 and XPA genes and clinical outcome for 38 pts with PEC, who received OXP (85 mg/m2 day (D)1, D15 and D29), PI 5FU (180 mg/m2 D8-D42 ) and XRT (5040 cGy beginning D8 for 28 fractions) TS appeared to be prognostic for survival (Leichman et al., Proc. ASCO, 22:263, 2003). Because recurrence and deaths have continued, an updated analysis for pts followed through October 2003 is presented including expression of DPD and MRP-2 genes. Methods: Pts had endoscopic biopsies of PEC prior to OXP (D1), prior to 5FU and XRT (D8) and at the end of treatment (ET). Gene expression was assayed typically in 2 specimens at each time point in 29 (ET) to 37 (D1) pts by real time QRT-PCR and expressed relative to β-actin. The mean mRNA levels at each time were logarithmically transformed and using Cox proportional hazards model with time-dependent covariates explored for relationships to survival (S) and progression free...

Thymidine kinase in epithelial ovarian cancer: relationship with the other pyrimidine pathway enzymes.

TK is a pyrimidine metabolic pathway enzyme involved in salvage DNA synthesis. What roles TK may play in epithelial ovarian cancer and the relationships between TK and the other pyrimidine pathway enzymes remain unclear. We examined TK1 gene expression by RT-PCR and related it to gene expression of TS, TP and DPD in 69 samples from epithelial ovarian cancer, 8 low-malignant-potential tumors, 16 benign ovarian tumors and 34 normal ovaries. Additionally, cytosolic and serum TK activities were determined by radioenzymatic assay. TK1 gene expression, the ratio of TK1 to TS gene expression, that of TK1 to TP and that of TK1 to DPD were significantly higher in epithelial ovarian cancer than in normal ovaries. In epithelial ovarian cancer, TK1 gene expression correlated with cytosolic and serum TK activities, TS and TP gene expression and the ratio of TP to DPD gene expression. Patients with high-TK1 gene expression had a significantly poorer survival than those with low TK1 gene expression. Combined analysis demonstrated that the relative risk of cancer death for tumors with high TK1, high TS and high TP gene expression was greater than that for tumors with high TK1 gene expression alone. TK1 gene expression together with TS, TP and DPD gene expression may play important roles in influencing the malignant behavior of epithelial ovarian cancer. Combination therapy including TK inhibitor is a possible therapeutic intervention in patients with epithelial ovarian cancer.

Common DPYD Mutation Associated with 5-Fluorouracil Toxicity Detected by PCR-mediated Site-directed Mutagenesis

The human dihydropyrimidine dehydrogenase gene (DPYD) encodes dihydropyrimidine dehydrogenase (DPD; EC 1.3.1.2), the first and rate-limiting enzyme in the three-step pathway of uracil and thymine catabolism. DPD is also the principal enzyme involved in detoxification of pyrimidine-based antimetabolic analogs, such as 5-fluorouracil (5-FU), a drug that is commonly used in the treatment of solid tumors (colon, breast, head, neck, ovary, and skin). Because >80% of the administered 5-FU is degraded by DPD (1), the DPD catalytic activity in cancer patients could affect the efficacy of 5-FU treatment. In cancer patients with very low DPD activity, toxic reactions (e.g., diarrhea, stomatitis, mucositis, myelosuppression, and neurotoxicity) were reported that in some cases were life-threatening and sometimes fatal (2). A frequency as high as 3% of putative heterozygotes for DPD deficiency was also estimated based on catalytic activities in population studies (3)(4). The identification and characterization of the human DPD cDNA (5) made possible the identification and molecular analysis of mutations that affect DPD expression and catalytic activity. The most common mutation (6) associated …