Thymidylate synthase quantitation and in vitro chemosensitivity testing predicts responses and survival of patients with isolated nonresectable liver tumors receiving hepatic arterial infusion chemotherapy

Are Colon and Rectal Cancer Two Different Tumor Entities? A Proposal to Abandon the Term Colorectal Cancer

Colon cancer (CC) and rectal cancer (RC) are synonymously called colorectal cancer (CRC). Based on our experience in basic and clinical research as well as routine work in the field, the term CRC should be abandoned. We analyzed the available data from the literature and results from our multicenter Research Group Oncology of Gastrointestinal Tumors termed FOGT to confirm or reject this hypothesis. Anatomically, the risk of developing RC is four times higher than CC, while physical activity helps to prevent CC but not RC. Obvious differences exist in molecular carcinogenesis, pathology, surgical topography and procedures, and multimodal treatment. Therefore, we conclude that CC is not the same as RC. The term "CRC" should no longer be used as a single entity in basic and clinical research as well as other areas of classification.

Thymidylate synthase: a predictive biomarker in resected colorectal liver metastases receiving 5-FU treatment

AIM

To investigate the role of thymidylate synthase (TS) as a predictive biomarker in patients with resected colorectal liver metastases (CRLM).

MATERIALS & METHODS

PubMed, EMBASE and Cochrane Library were queried up to June 2017. Meta-analysis was performed using random-effects model. Risk of bias was assessed using funnel plots.

RESULTS

Six eligible studies were included, comprising a total of 542 patients. Meta-analysis demonstrated a trend to reduced overall survival in patients with resected CRLM with TS overexpression, with a hazard ratio of 1.13 (95% CI: 0.99-1.29; p = 0.08). In three studies where patients received systemic fluorouracil, the pooled hazard ratio was 2.25 (95% CI: 1.37-3.71; p = 0.001).

CONCLUSION

TS appears to be a clinically relevant predictive biomarker in patients with resected CRLM receiving systemic 5-FU.

Shifting from clinical to biologic indicators of prognosis after resection of hepatic colorectal metastases

Following resection of hepatic colorectal metastases, there are few criteria for predicting which patients have more aggressive disease and are, therefore, more likely to experience recurrence and reduced survival. Traditionally, primary tumor stage, preoperative carcinoembryonic antigen level, time from primary tumor treatment to diagnosis of hepatic metastases (disease-free interval), hepatic tumor size, number of hepatic metastases, and presence of extrahepatic disease have been reported to be predictors of survival after resection. However, the data regarding the prognostic importance of these clinicopathologic factors are inconsistent and conflicting. Therefore, conventional clinicopathologic factors may be inadequate for the purposes of prognostication. More recently, there has been increased interest in identifying biologic indicators that may help better define patients at risk for recurrence after hepatic resection for colorectal metastases. Recent studies have shown that proliferation markers such as p53 expression, tritiated thymidine uptake, thymidylate synthase, Ki-67, and human telomerase reverse transcriptase may be better predictors of outcome after resection of hepatic colorectal metastases. Moreover, tumor response to preoperative chemotherapy may also prove to be a useful predictor of outcome following liver resection for colorectal metastases.

Thymidine phosphorylase mRNA level predicts survival of patients with advanced oropharyngeal cancer

CONCLUSION

The present study suggested that a high level of thymidine phosphorylase (TP) gene expression is significantly associated with favorable prognosis of patients treated with 5-fluorouracil (5-FU)-based chemotherapy. Further studies consisting of large series should be performed to confirm our present results.

BACKGROUND

Expression levels of the thymidylate synthase (TS) and 5-FU metabolic enzymes including dihydropyrimidine dehydrogenase (DPD), TP, and orotate phosphoribosyl transferase (OPRT), are reported to be associated with sensitivity to 5-FU-based chemotherapy in several cancers.

PATIENTS AND METHODS

Intratumoral mRNA expression levels of TS, DPD, TP, and OPRT in pretreatment biopsy specimens were quantified in 27 patients with advanced oropharyngeal squamous cell carcinomas. Association of these expression levels with response to platinum and 5-FU-based chemotherapy and survival were analyzed statistically.

RESULTS

By Spearman's correlation analysis, significant correlation was observed between TS and TP (gamma=0.51, p=0.018). While no correlation was observed between the tumor regression and expression of any of the genes investigated, significant association was observed between prognosis and mRNA expression levels of TS and TP. Multivariate Cox regression analysis revealed that TP mRNA expression level is a significant factor predicting prognosis (hazard ratio (HR) = - 0.204, p=0.043).

Involvement of gene polymorphisms of thymidylate synthase in gene expression, protein activity and anticancer drug cytotoxicity using the NCI-60 panel

A significant association has been established, in clinical studies, between the expression or activity of thymidylate synthase (TYMS) and the efficiency of fluorouracil. TYMS expression is partly under the dependence of gene polymorphisms in the 5' and 3' untranslated regions (UTR), but conflicting results have been obtained about their roles on fluorouracil efficiency. In this study, we wanted to use the National Cancer Institute (NCI) panel of 60 human tumour cell lines to clarify this problem. Three relevant polymorphisms of the TYMS gene were studied: (i) the 5'UTR tandem repeat of 28-bp (2R/3R polymorphism); (ii) the single nucleotide polymorphism (SNP) within the second repeat (3C/3G polymorphism); (iii) the 3'UTR 6-bp deletion (+6/-6 polymorphism). Allele frequencies were close to those expected in a Caucasian population (2R/3C/3G: 53/29/18%; +6/-6: 68/32%), but the proportion of heterozygous genotypes was lower than expected from allele frequencies. The 2R and 3G alleles were significantly associated with the +6 and the -6 alleles, respectively. There was a significant association between the presence of the 3G allele and TYMS mRNA expression and catalytic activity, particularly in p53-mutated cell lines. However, no significant correlation existed between fluorouracil cytotoxicity, as extracted from the NCI databases, and TYMS expression, activity or polymorphisms.

Preclinical evaluation of the pharmacodynamic properties of 2,5-diaziridinyl-3-hydroxymethyl-6-methyl-1,4-benzoquinone

PURPOSE

The purpose of our study was to investigate the cellular accumulation, DNA cross-linking ability, and cellular toxicity of RH1 (2,5-diaziridinyl-3-[hydroxymethyl[-6-methyl-1,4-benzoquinone), a novel DNA alkylating agent currently in clinical trials. In addition, the in vivo efficacy of RH1 formulated in different vehicles was also compared.

EXPERIMENTAL DESIGN

RH1 is activated by the two-electron reducing enzyme NQO1 [NADPH:quinone oxidoreductase] forming a potent cytotoxic agent that cross-links DNA. We have used whole blood, cell lines, and primary explanted tumor cultures to measure both the cellular accumulation, DNA cross-linking, and cytotoxicity of RH1. Furthermore, the pharmacokinetic and pharmacodynamic characteristics of RH1 formulated in different vehicles were measured in vivo using the validated comet-X assay in mice bearing human tumor xenografts.

RESULTS

Accumulation of RH1 was shown to be both time and concentration dependent, reaching a maximum after 2 hours and correlated well with DNA cross-linking measurements. DNA cross-linking in vitro could be detected at low (1-10 nmol/L) concentrations after as little as 2 hours exposure. In primary tumor cultures, RH1 induces much higher levels of DNA cross-links at lower doses than either mitomycin C or cisplatin. In vivo efficacy testing using polyvinyl pyrrolidone, saline, or cyclodextrin as vehicles showed DNA cross-links readily detectable in all tissues examined and was enhanced when given in cyclodextrin compared with polyvinyl pyrrolidone or saline.

CONCLUSIONS

RH1 represents a potent bioreductive anticancer drug, which may prove effective in the treatment of cancers, particularly those that overexpress NQO1. DNA cross-linking can be reliably measured in tissue using the validated comet-X assay.

Pharmacogenetic influences on treatment response and toxicity in colorectal cancer

Current use of chemotherapeutic and targeted agents for advanced colorectal cancer (CRC) results in high tumor response rates and relatively long overall patient survival. Fluoropyrimidines, irinotecan, and oxaliplatin are highly active in first-line and salvage therapy of colorectal cancer. Targeted therapies, including anti-angiogenesis agents and anti-epidermal growth factor receptor antibodies, have been incorporated with traditional chemotherapy and offer additional options for patients with CRC. However, there is marked variability in response to therapy, as well as frequency and severity of toxicities. Molecular markers and pharmacogenomic profiling may improve prediction of patients who will experience significant benefit or toxicity from currently available agents. Validation of these predictive factors in prospective clinical trials is now necessary to allow for a rational and systematic individualization of cancer therapy.

Colon cancer: survival after curative surgery

Several new aspects have evolved during the past years concerning factors that influence survival in surgically and medically treated colon cancer patients that are relevant to the treating team for the treatment strategy and patient's choice. The 5-year-survival rates dependent on UICC stages/substages (I: 68%-100%, II: 58%-90%, III: 33%-76%, IV: <5%-9%) show remarkable variations between published reports, surgical hospital units, individual surgeons, and continents (USA vs Europe). Those variations may be due to surgical techniques, training status, hospital and individual case volume, and, also, referral patterns and statistical evaluation methods. Survival times and cure rates are significantly improved by adjuvant chemotherapy in UICC III and in substages of UICC II (e.g. UICC II B) by 5%-12%, when compared with surgical controls. In three recently published trials standard adjuvant chemotherapy was further improved by increased survival rates, e.g. from 59% to 71% in stage III and IIB patients. Molecular and genetic factors, such as thymidylate synthase (TS), microsatellite instability (MSI) or loss of chromosome 18q/"DCC" might have an independent impact on prognosis in the spontaneous course, and TS could help to better select patients for adjuvant chemotherapy.

A longterm follow-up study of thymidylate synthase as a predictor for survival of patients with liver tumours receiving hepatic arterial infusion chemotherapy

AIMS

Thymidylate synthase (TS) is a key-enzyme for DNA synthesis and targeted by fluoropyrimidines (FPs). High TS ratios are associated with resistance to systemic FP-based chemotherapy. The aim of this study was to report the influence of TS ratios on primary tumour response to FP-based HAI and long-term follow-up of patients with isolated non-resectable liver tumours in part from a previously published study.

METHODS

Fifty-one consecutive patients with liver tumours receiving HAI with available tumour tissue for TS quantitation were studied between 1991 and 2001. Liver metastases were from colorectal origin in 41 patients and other primary sites in 6 patients. Four patients had primary liver cancers. Tumour tissue was obtained at laparotomy for the intraarterial infusion device implantation. TS mRNA quantitation was performed by RT-PCR using beta-actin as internal standard.

RESULTS

The median TS ratio was 2.2 with high variation among tumours ranging from 0.1 to 27. Twenty-two out of 51 patients responded to HAI. The median TS ratio of the responders was 1.6 and more than two-fold lower than the ratio of the non-responders with 3.3 (p < 0.01). In the subgroup with TS<or=3.0, 18 out of 29 patients responded. In the subgroup with TS>3.0 only four out of 22 patients responded. No patients with very high TS ratios >or=4.5 ( n = 13) responded to HAI. Median survival was 20 months (range: 3-109). Patients with TS-ratios <or=3.0 showed, with 55%, a higher 2-year survival rate than patients with TS-ratios >3.0 with 27%.

CONCLUSION

TS seems to be a predictive and prognostic factor for patients with isolated non-resectable liver tumours receiving FP-based HAI. Patients with very high TS ratios do not seem to benefit from FP-based HAI.

Clonogenic assay with established human tumour xenografts: correlation of in vitro to in vivo activity as a basis for anticancer drug discovery

Pluripotent cells can be grown in clonogenic assays. The tumour stem-cell fraction, which accounts for <0.4% of the total cells, and which is considered the most relevant cell type in the development of metastases and recurrences, is able to divide and to form colonies in a semisolid matrix (agar or methylcellulose). Major applications of the tumour clonogenic assay (TCA) are chemosensitivity testing of tumours and xenografts, and for assessments within drug discovery programmes. Of critical relevance for the usefulness of the TCA is whether it can predict sensitivity or resistance towards clinically used agents. When we compared the response of human tumours established as xenografts in nude mice in the TCA in vitro to that of the clinical response, 62% of the comparisons for drug sensitivity, and 92% of the comparisons for drug resistance were correct. The same percentage of true/false observations was found when tumours were tested after serial passage in nude mice in the TCA in vitro and their response compared to in vivo activity in corresponding xenografts (60% and 90%, respectively). The highest correct predictive values were, however, found when the clinical response of tumours was compared to their explants established in the nude mouse and treated in vivo. Of 80 comparisons performed, we observed a correct prediction for tumour resistance in 97% and for tumour sensitivity in 90%. In our opinion, the TCA with established human tumour xenografts has an important role in current drug discovery strategies. We therefore included the TCA as secondary assay in our approach to anticancer drug discovery and found that a number of novel agents were active; these are now in advanced preclinical development or clinical trials. Thus, the tumour clonogenic assay has proven predictive value in the chemosensitivity testing of standard and experimental anticancer drugs.

Thymidylate synthetase mRNA levels are increased in liver metastases of colorectal cancer patients resistant to fluoropyrimidine-based chemotherapy

Background

Fluoropyrimidines such as 5-fluorouracil (5-FU) and 5-fluoro-2'deoxyuridine (FUDR) are among the most effective chemotherapeutic agents for treatment of metastatic colorectal cancer (CRC). Increased expression of thymidylate synthetase (TS) in CRC metastases has been proposed to be an important mechanism of resistance to fluoropyrimidine-based chemotherapy.

Methods

The present study investigated whether TS mRNA levels in liver metastases of 20 CRC patients before treatment with FUDR by hepatic arterial infusion (HAI) correlated with frequency of clinical response or survival duration.

Results

Median survival duration of patients with TS mRNA levels above and below the median was 15 and 18 months, respectively (p > 0.05). Clinical response was achieved in 40% of patients with low TS mRNA levels, but in only 20% of patients with high TS mRNA levels (p = 0.01). TS mRNA levels were also measured for liver metastases of 7 of the patients that did not achieve a clinical response. A statistically significant increase in expression of TS mRNA was observed for liver metastases resistant to chemotherapy (21 ± 14) in comparison to liver metastases of the same patients before chemotherapy (8 ± 4) (p = 0.03).

Conclusion

This is the first report to demonstrate increased TS expression in liver metastases from CRC patients resistant to fluoropyrimidine based chemotherapy. These findings are consistent with previous studies indicating that increased TS expression is associated with resistance to fluoropyrimidine-based chemotherapy.

Thymidylate synthase expression and prognosis in colorectal cancer: a systematic review and meta-analysis

PURPOSE

A number of studies have investigated the relationship between thymidylate synthase (TS) expression and survival in colorectal cancer (CRC) patients. Although most have reported poorer overall and progression-free survival with high TS expression, estimates of the hazard ratio (HR) between studies differ wildly. To derive a more precise estimate of the prognostic significance of TS expression, we have reviewed published studies and carried out a meta-analysis.

MATERIALS AND METHODS

Twenty studies stratifying overall survival and/or progression-free survival in CRC patients by TS expression status were eligible for analysis. The principal outcome measure was the HR. Data from these studies were pooled using standard meta-analysis techniques.

RESULTS

Thirteen studies investigated outcome in a total of 887 cases with advanced CRC, and seven studies investigated outcome in a total of 2,610 patients with localized CRC. A number of methods were used both to assess TS expression and to assign TS status. Sample sizes varied greatly, small sample sizes being a feature of the advanced disease studies. The combined HR estimate for overall survival (OS) was 1.74 (95% CI, 1.34 to 2.26) and 1.35 (95% CI, 1.07 to 1.80) in the advanced and adjuvant settings, respectively, but there was evidence of heterogeneity and possible publication bias.

CONCLUSION

Tumors expressing high levels of TS appeared to have a poorer OS compared with tumors expressing low levels. Additional studies with consistent methodology are needed to define the precise prognostic value of TS.

Intraperitoneal chemotherapy with mitoxantrone in malignant ascites

A retrospective analysis of intraperitoneal mitoxantrone instillation therapy for malignant ascites in advanced breast and gynecologic pelvic cancers was performed to confirm the efficacy and safety of this therapy. Several smaller phase II trials had suggested good palliative effects. In 143 patients (37 breast cancer and 106 gynecologic cancers), 257 instillations were registered. Response in breast cancer was induced in 49% and in 63% with gynecologic cancer. Severe or life-threatening clinical or laboratory side effects related to intraperitoneal mitoxantrone occurred in 2.7% (clinical) or 1.9% (laboratory) of the 257 instillations. Induction of adverse side effect was dose dependent. Intraperitoneal chemotherapy with mitoxantrone for treatment of malignant ascites in breast cancer and gynecologic malignancy is effective and well tolerated. For this treatment 30 mg mitoxantrone in > or = 1000 mL carrier solution (e.g., saline) is recommended. A minimal concentration of at least 10 micrograms/mL should be achieved.

Chemosensitivity testing and test-directed chemotherapy in human pancreatic cancer

Human pancreatic cancer is a devastating disease with poor prognosis. In many cases it is diagnosed at stages in which a complete resection is not possible. However, even after complete resection most tumors recur. Therefore, several chemotherapeutic strategies have been developed, so far, with little impact on the clinical outcome. Because one of the hallmarks of human pancreatic cancer is its general resistance to chemotherapeutic agents, it seems important to develop strategies to individualize chemotherapy and to render cells more sensitive to chemotherapeutic agents. In this summary we describe our methods of in vitro chemosensitivity testing using the human tumor colony-forming assay for pancreatic cancer in comparison with other solid tumors and describe how the in vitro results influence chemotherapy. Furthermore, we point out new developments of mRNA quantitation of chemoresistance target enzymes based on real-time PCR, which may help in the future to individualize chemotherapy of pancreatic cancer. Finally, we present results of studies of cyclin D1 inhibition. Suppression of cyclin D1 by cyclin D1 antisense mRNA expression was associated with growth inhibition and an increase in chemosensitivity to fluoropyrimidines and platinum compounds. Because human pancreatic cancers are relatively chemoresistant and material for chemosensitivity testing with the human tumor colony-forming assay (HTCA) is in most cases difficult to obtain, future investigations should aim at the development of methods requiring only very small samples to analyzemarkers of chemosensitivity. Our results further suggest that chemotherapy in combination with strategies to increase chemosensitivity may be a reasonable regimen for the treatment of human pancreatic cancer in the future.

Thymidylate synthase expression in hepatic tumors is a predictor of survival and progression in patients with resectable metastatic colorectal cancer

PURPOSE

To investigate the role of thymidylate synthase (TS),p53, and epidermal growth factor receptor (EGF-R) expressions in hepatic tumors in predicting overall survival (OS), progression-free survival (PFS), and hepatic progression-free survival (HPFS) in patients with resectable metastatic colorectal cancer who were randomly assigned to receive either systemic chemotherapy (SYS) alone or systemic and hepatic arterial infusion (HAI+SYS) chemotherapy following liver surgery.

PATIENTS AND METHODS

Tissues from metastatic tumors were collected during liver resection from 156 patients, and marker expressions were determined using immunohistochemistry on frozen samples. Univariate associations between marker expressions and baseline variables with OS, PFS, and HPFS were examined. Independent predictors of outcome were determined using a multivariate Cox model.

RESULTS

In multivariate analyses, TS overexpression was found to be an independent factor of poor prognosis in OS (P <.01), PFS (P =.06), and HPFS (P <.01). In addition, resection margin was a significant independent factor for all three outcomes. Patients who received HAI+SYS experienced delayed progression in general, and in the liver, specifically. Increased levels of serum alkaline phosphatase correlated with hepatic progression. We also found a significant TS-treatment interaction for OS (P =.01) in multivariate analysis. In particular, TS+ patients receiving HAI+SYS had significantly higher survival than those receiving SYS (64 month sv 21 months; P =.01).

CONCLUSION

TS levels in hepatic tumors and resection margin are independent predictors of survival and progression in patients with metastatic colorectal cancer, whereas p53 and EGFR are not independent predictors. Treatment with HAI + SYS significantly improved the survival profile of TS+ patients.

Arterial chemotherapy as adjuvant and palliative treatment of hepatic colorectal metastases: an update

Regional hepatic chemotherapy with FUDR significantly improves local recurrence rates and may impact overall survival in patients with hepatic colorectal metastases. The results of prospective randomized trials confirm that careful patient selection, a thorough knowledge of intricate hepatic arterial anatomy, and an understanding of the pharmacokinetics and delivery of FUDR optimize treatment efficacy. A multimodality approach that includes adjuvant therapy in addition to cytoreductive surgery offers promise for the treatment of unresectable hepatic metastases. Because many tumors recur in extrahepatic sites, the addition of novel systemic agents such as CPT-11 may further reduce recurrences. Molecular analysis of the tumor may ultimately help select patients who are good candidates for regional chemotherapy.

Future potential of thymidylate synthase inhibitors in cancer therapy

Thymidylate synthase (TS) catalyses the de novo synthesis of deoxythymidylate and is a key rate-limiting enzyme of DNA synthesis. The primary site of action of the classic antifolate methotrexate is direct inhibition of dihydrofolate reductase, but it also inhibits TS indirectly by diminishing levels of the TS cosubstrate 5,10-methylenetetrahydrofolate. Polyglutamated metabolites of methotrexate also directly bind and inhibit TS. The prototype fluoropyrimidine fluorouracil is metabolised to an irreversible inhibitor of TS and is the standard chemotherapy for gastrointestinal carcinomas. It is also frequently used in combination with other anticancer drugs against breast cancer and head and neck cancers. The clinical efficacy of fluorouracil is routinely increased by concomitant administration of the biomodulating compound leucovorin (folinic acid). Both the success and limitations of these early drugs led to a search for new, more efficacious TS inhibitors active against a broader range of neoplasms. Raltitrexed (ZD1694, Tomudex) is an antifolate TS inhibitor developed over the last decade that is similarly effective, yet better tolerated, than fluorouracil against colorectal cancer. Additional antifolate and fluoropyrimidine-based TS inhibitors continue to be developed. Many of these experimental drugs have been designed to exploit or thwart selective metabolism in neoplasms, including specific mechanisms of resistance. As the curative potential of relatively non-selective antiproliferative drugs like TS inhibitors is limited against most neoplasms, the future role of TS inhibitors will likely continue to be adjunctive in surgically resectable tumours and palliative in combination with other agents for non-resectable disease. Although TS inhibitors will eventually be supplanted by yet to be discovered agents targeting more tumour-specific cellular signalling pathways, they will probably remain important for the above uses for some time. Future advances in the effective use of TS inhibitors may be forthcoming in the form of improved dosing, fewer untoward effects and increased tumour selectivity with novel fluorouracil prodrug formulations. Furthermore, there is emerging evidence that some novel antifolate TS inhibitors are active against a broader range of neoplams, including lung carcinomas and mesothelioma, compared to classical TS inhibitors. Other possible advances to come include effective biomodulation of antifolate TS inhibitors with nucleoside transport inhibitors and individualised patient therapy based on tumour gene expression and resistance patterns (pharmacogenetics).

Regional chemotherapy of nonresectable colorectal liver metastases with mitoxantrone, 5-fluorouracil, folinic acid, and mitomycin C may prolong survival

BACKGROUND

Regional chemotherapy of isolated, nonresectable colorectal liver metastases (CRLMs) by hepatic artery infusion (HAI) has the advantages of high response rates and the possibility of downstaging and resection of CRLMs. 5-Fluorodeoxyuridine (5-FUDR) has been the drug studied in most Phase II and III trials. The meta-analysis of the Phase III trials comparing HAI with systemic or supportive therapy confirmed an advantage for response and even survival for HAI. Hepatic artery infusion with 5-FUDR, however, is hepatotoxic, inducing sclerosing cholangitis (SC). The authors have introduced 5-fluorouracil (5-FU) with folinic acid for HAI and found equal effectivity but no SC when compared with HAI with 5-FUDR. Now, they report a new combination chemotherapy protocol based on HAI with 5-FU with FA and on in vitro Phase II studies suggesting mitoxantrone and mitomycin C as active drugs for HAI in CRLM. PATIENTS AND METHODS Between February 1993 and August 2000, 63 patients with CRLM were treated with HAI using mitoxantrone, 5-FU with FA, and mitomycin C (MFFM) via port catheters with a protocol planing up to 11 cycles of treatment. Toxicity and response were analyzed according to World Health Organization (WHO) criteria, and survival was analyzed according to Kaplan-Meier. All patients were treated with more than two HAI cycles.

RESULTS

The objective response rate (complete remission and partial remission) was 54% and primary intrahepatic progression (progressive disease) occurred in 4.8%, whereas in 41.3% of the patients the intrahepatic disease was evaluated as no change. Median survival times from the first diagnosis of CRLM or start of HAI were 25.7 months and 23.7 months, respectively, and 7 patients lived longer than 40 months. Grade 3 toxicity according to WHO occurred in 34.9%, and Grade 4 occurred in 3.2%. No toxic death or SC occurred.

CONCLUSIONS

Our new HAI protocol with MFFM seems to be superior to HAI with 5-FUDR, 5-FU with FA, and systemic chemotherapy with 5-FU and FA at acceptable toxicity. Currently, HAI with MFFM is compared with systemic chemotherapy using 5-FU and FA intravenously in a randomized Phase III trial.

Pharmacogenetic determinants of anti-cancer drug activity and toxicity

Cellular responses to anti-cancer agents result from the interaction between drugs, cellular targets and mechanisms of damage repair. Despite the pharmacological advances in the treatment of cancer, the clinical efficacy of chemotherapy is unpredictable in most patients. However, new information on the genetics of cancer delineates strategies by which the genetic background of tumour cells and patients might be profiled to select anti-cancer agents with improved efficacy and tolerability. This article focuses on the application of pharmacogenetics in the characterization of differences in the pharmacokinetics and pharmacodynamics of anti-cancer agents among individuals to define the likelihood of response and reduce the incidence of adverse effects.