Comparison of gemcitabine versus the matrix metalloproteinase inhibitor BAY 12-9566 in patients with advanced or metastatic adenocarcinoma of the pancreas: a phase III trial of the National Cancer Institute of Canada Clinical Trials Group

Advanced pancreatic cancer: flourishing novel approaches in the era of biological therapy

The progress in the development of systemic treatment for advanced pancreatic cancer (APC) has been slow. The mainstream treatment remains using chemotherapy including gemcitabine, FOLFIRINOX, and nab-paclitaxel. Erlotinib is the only approved biological therapy with marginal benefit. Studies of agents targeting epidermal growth factor receptor, angiogenesis, and RAS signaling have not been satisfying, and the usefulness of targeted therapy in APC is uncertain. Understanding in molecular processes and tumor biology has opened the door for new treatment strategies such as targeting insulin-like growth factor 1 receptor, transforming growth factor β, phosphoinositide 3-kinase/AKT/mammalian target of rapamycin pathway, and Notch pathway. New directions also include the upcoming immunotherapy and many novel agents that act on the microenvironment. The practice of personalized medicine using predictive biomarkers and pharmacogenomics signatures may also enhance the effectiveness of existing treatment. Future treatment approaches may involve comprehensive genomic assessment of tumor and integrated combinations of multiple agents to overcome treatment resistance.

Smarter drugs emerging in pancreatic cancer therapy

Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancer death in the Western world. Owing to a lack of specific symptoms and no accessible precursor lesions, primary diagnosis is commonly delayed, resulting in only 15%-20% of patients with potentially curable disease. The standard of care in advanced pancreatic cancer has improved. Apart from gemcitabine (plus erlotinib), FOLFIRINOX and the combination of gemcitabine plus nab-paclitaxel are novel and promising therapeutic options for patients with metastatic PDAC. A better molecular understanding of pancreatic cancer has led to the identification of a variety of potential molecular therapeutic targets. Many targeted therapies are currently under clinical evaluation in combination with standard therapies for PDAC. This review highlights the current status of targeted therapies and their potential benefit for the treatment of advanced PDAC.

Personalising pancreas cancer treatment: When tissue is the issue

The treatment of advanced pancreatic cancer has not moved much beyond single agent gemcitabine until recently when protocols such as FOLFIRINOX (fluorouracil, leucovorin, irinotecan and oxaliplatin) and nab-paclitaxel-gemcitabine have demonstrated some improved outcomes. Advances in technology especially in massively parallel genome sequencing has progressed our understanding of the biology of pancreatic cancer especially the candidate signalling pathways that are involved in tumourogenesis and disease course. This has allowed identification of potentially actionable mutations that may be targeted by new biological agents. The heterogeneity of pancreatic cancer makes tumour tissue collection important with the aim of being able to personalise therapies for the individual as opposed to a one size fits all approach to treatment of the condition. This paper reviews the developments in this area of translational research and the ongoing clinical studies that will attempt to move this into the everyday oncology practice.

Systemic treatment for inoperable pancreatic adenocarcinoma: review and update

There have been many clinical trials conducted to evaluate novel systemic regimens for unresectable pancreatic cancer. However, most of the trial results were negative, and gemcitabine monotherapy has remained the standard systemic treatment for years. A number of molecular targeted agents, including those against epidermal growth factor receptor and vascular endothelial growth factor receptors, have also been tested. In recent years, there have been some breakthroughs in the deadlock: three regimens, namely gemcitabine-erlotinib, FOLFIRINOX, and gemcitabine-nab-paclitaxel, have been shown to prolong the overall survival of patients when compared with gemcitabine monotherapy. In addition, emerging data suggested that the membrane protein human equilibrative nucleotide transporter 1 is a potential biomarker with which to predict the efficacy of gemcitabine. Here we review the literature on the development of systemic agents for pancreatic cancer, discuss the current choices of treatment, and provide future directions on the development of novel agents.

Intensified chemotherapy and simultaneous treatment with heparin in outpatients with pancreatic cancer - the CONKO 004 pilot trial

Background

Advanced pancreatic cancer (APC), beside its high mortality, causes the highest rates of venous thromboembolic events (VTE). Enoxaparin, a low molecular weight heparin (LMWH), is effective in prevention and treatment of VTE. Some small studies indicated that this benefit might extend to patients with cancer and probably prolong survival due to independent mechanisms. We initiated this safety investigation to get feasibility information on intensified chemotherapy combined with LMWH in outpatients with APC treated in 1^st line.

Methods

The trial was a prospective, open-label, single center investigation in outpatients with inoperable pancreatic cancer who were treated with intensified first-line chemotherapy along with concomitant application of subcutaneous LMWH. The combined chemotherapy consisted of gemcitabine 1 g/m² (30 min), 5-FU 750 mg/m² (24 h), folinic acid 200 mg/m² (30 min), and Cisplatin 30 mg/m² (90 min) on day 1 and 8; q3w for the first 12 weeks (GFFC) followed by gemcitabine alone in patients without cancer progression. The simultaneous application of prophylactic enoxaparin started on day 1 of chemotherapy with a fixed dose of 40 mg daily. Statistical analyses were performed using R 3.01 with software package CMPRSK and SPSS software v19.0.

Results

The investigation was stopped after recruitment of 19 patients. At this time 15 patients had completed the required 12 weeks of treatment. Based on 71 cycles of GFFC + enoxaparin (median 4/pt [range: 2–4]) and 108 cycles of single-agent gemcitabine + enoxaparin (median 4/pt [range: 0–18]) the cumulative frequency of NCI-CTC toxicities grade 3/4 was below 10%. One case (5%) of a symptomatic non-lethal thromboembolic event was observed while receiving LMWH treatment. No severe bleeding event as defined in the protocol has been observed. The median overall survival was 10.05 [95% CI: 8.67-18.14] months.

Conclusions

The addition of enoxaparin to GFFC chemotherapy is feasible, safe and does not appear to affect the efficacy or the toxicity profile of the chemotherapy regimen in patients with advanced pancreatic adenocarcinoma. Based on these findings we have initiated the randomized CONKO-004 trial to examine whether enoxaparin reduces the incidence of thromboembolic events or increases overall outcome.

Trial registration

Clinical Trials NCT01945879.

Pancreatic cancer stroma: Understanding biology leads to new therapeutic strategies

Pancreatic ductal adenocarcinoma (PDA) is among the deadliest cancers in the United States and in the world. Late diagnosis, early metastasis and lack of effective therapy are among the reasons why only 6% of patients diagnosed with PDA survive past 5 years. Despite development of targeted therapy against other cancers, little progression has been made in the treatment of PDA. Therefore, there is an urgent need for the development of new treatments. However, in order to proceed with treatments, the complicated biology of PDA needs to be understood first. Interestingly, majority of the tumor volume is not made of malignant epithelial cells but of stroma. In recent years, it has become evident that there is an important interaction between the stromal compartment and the less prevalent malignant cells, leading to cancer progression. The stroma not only serves as a growth promoting source of signals but it is also a physical barrier to drug delivery. Understanding the tumor-stroma signaling leading to development of desmoplastic reaction and tumor progression can lead to the development of therapies to decrease stromal activity and improve drug delivery. In this review, we focus on how the current understanding of biology of the pancreatic tumor microenvironment can be translated into the development of targeted therapy.

Pigment epithelium-derived factor as a natural matrix metalloproteinase inhibitor: a comparison with classical matrix metalloproteinase inhibitors used for cancer treatment

OBJECTIVES

In the 1990s, the discovery of the important role of matrix metalloproteinases (MMPs) in cancer angiogenesis, growth and metastasis galvanised research efforts to search for ways to inhibit these MMPs. To date, this has resulted in the investigation of approximately 50 MMPIs which have undergone various phases of clinical trials. However, despite a large body of research being devoted to discovery and development of MMPIs, results have largely not been supportive of this approach to anticancer treatment.

KEY FINDINGS

The reasons for the general failure of these drugs in clinical trials include various unwanted side-effects, the use of healthy volunteers to provide drug dosages which did not correctly reflect dosages for cancer patients, and the exclusion of patients with early stage cancer in clinical trials despite MMPs being determined to be critical for the angiogenic switch, a process associated with early tumour growth. In contrast, a naturally-occurring endogenous protein and a non-functional serine protease inhibitor (serpin), pigment epithelium-derived factor (PEDF), has been proposed for cancer therapy partly due to its ability to regulate specific MMPs central to cancer progression.

SUMMARY

PEDF has been found to specifically downregulate membrane-type I matrix metalloproteinase (MT1-MMP) and furthermore, potentially matrix metalloproteinase-2 (MMP-2), two of the most commonly implicated MMPs in neoplasia.

Erlotinib

The epidermal growth factor receptor (EGFR) has been implicated in a multiplicity of cancer-related signal transduction pathways such as cellular proliferation, adhesion, migration, neoangiogenesis and apoptosis inhibition, all of them are important features of cancerogenesis and tumour progression. Its tyrosine kinase activity plays a central role in mediating these processes and has been intensely studied to exploit it as a therapeutic target. Inhibitors of this pathway have been developed and assessed in trials with significant efficacy in clinical applications. The current review focuses in particular on the clinical data of EGFR tyrosine kinase inhibition in different tumour entities, preferably non-small cell lung cancer and pancreatic cancer with emphasis to the approved small molecule erlotinib. Its clinical applications, evidence-based efficacy and toxicity as well as predictive markers of response are discussed.

Molecular targets in the discovery and development of novel antimetastatic agents: current progress and future prospects

Tumour invasion and metastasis have been recognized as major causal factors in the morbidity and mortality among cancer patients. Many advances in the knowledge of cancer metastasis have yielded an impressive array of attractive drug targets, including enzymes, receptors and multiple signalling pathways. The present review summarizes the molecular pathogenesis of metastasis and the identification of novel molecular targets used in the discovery of antimetastatic agents. Several promising targets have been highlighted, including receptor tyrosine kinases, effector molecules involved in angiogenesis, matrix metalloproteinases (MMPs), urokinase plasminogen activator, adhesion molecules and their receptors, signalling pathways (e.g. phosphatidylinositol 3-kinase, phospholipase Cγ1, mitogen-activated protein kinases, c-Src kinase, c-Met kinases and heat shock protein. The discovery and development of potential novel therapeutics for each of the targets are also discussed in this review. Among these, the most promising agents that have shown remarkable clinical outcome are anti-angiogenic agents (e.g. bevacizumab). Newer agents, such as c-Met kinase inhibitors, are still undergoing preclinical studies and are yet to have their clinical efficacy proven. Some therapeutics, such as first-generation MMP inhibitors (MMPIs; e.g. marimastat) and more selective versions of them (e.g. prinomastat, tanomastat), have undergone clinical trials. Unfortunately, these drugs produced serious adverse effects that led to the premature termination of their development. In the future, third-generation MMPIs and inhibitors of signalling pathways and adhesion molecules could form valuable novel classes of drugs in the anticancer armamentarium to combat metastasis.

Pooled survival and response data from phase III randomized controlled trials for gemcitabine-based regimes in the treatment of advanced pancreatic cancer

Although gemcitabine remains current first-line chemotherapy for patients with advanced pancreatic cancer, median survival times have not improved significantly since its introduction 15 years ago. Of the phase III trials which have investigated alternative regimens to single-agent gemcitabine, most have used combination regimens as the investigational arm. Accurate data on median overall, progression-free survival and objective response rates is important, for two principle reasons: advising patients about their prognosis and when powering phase II trials and evaluating the results of single-armed trials. This study aims to pool results from published randomized trials to date. Twenty-one randomized phase III trials involving a total of 6348 patients were identified from 1997 to 2010. Only one trial investigating a novel agent in combination with gemcitabine showed a significantly prolonged median and progression-free survival compared with single-agent gemcitabine. Pooled median and progression-free survivals for the single-agent gemcitabine arm involving 3171 patients across all studies were 6.15 and 3.3 months, respectively. Length of survival for patients with advanced pancreatic cancer remains disappointing. Further trials of novel agents to complement or replace gemcitabine are indicated.

From bench to bedside: lessons learned in translating preclinical studies in cancer drug development

The development of targeted agents in oncology has rapidly expanded over the past 2 decades and has led to clinically significant improvements in the treatment of numerous cancers. Unfortunately, not all success at the bench in preclinical experiments has translated to success at the bedside. As preclinical studies shift toward defining proof of mechanism, patient selection, and rational drug combinations, it is critical to understand the lessons learned from prior translational studies to gain an understanding of prior drug development successes and failures. By learning from prior drug development, future translational studies will provide more clinically relevant data, and the underlying hope is that the clinical success rate will improve and the treatment of patients with ineffective targeted therapy will be limited.

Monoclonal antibodies and other targeted therapies for pancreatic cancer

Pancreatic cancer continues to be a challenging disease to treat because of its aggressive nature, advanced stage at the time of diagnosis, and limited treatment options that are available. Traditional cytotoxic chemotherapy provides modest benefit to patients with pancreatic adenocarcinoma. Recently, a FOLFIRINOX regimen revealed improved response in overall and progression-free survival over single-agent gemcitabine in metastatic pancreatic cancer, but there is still much needed advancement in the systemic treatment of pancreatic cancer. There is a growing interest in the development of novel agents, while our understanding of molecular pathogenesis of pancreatic adenocarcinoma continues to expand. With identification of various molecular pathways in pancreatic cancer tumorigenesis, potential targets for drug development have been pursued with the use of monoclonal antibodies and small-molecule inhibitors. Although preclinical studies with multiple targeted therapies demonstrated encouraging results in pancreatic cancer, only erlotinib, an epidermal growth factor receptor inhibitor, showed a marginal survival benefit in a phase III clinical trial, when combined with gemcitabine. As further signaling pathways and their importance in pancreatic cancer tumorigenesis are better understood, further clinical trials will need to be designed to study these targeted agents as single agents, in combination with other novel agents or in combination with cytotoxic chemotherapy. In this review, we present the current knowledge on targeted therapy in pancreatic adenocarcinoma and its application in clinical practice.

Molecularly targeted therapies in metastatic pancreatic cancer: a systematic review

Pancreatic cancer is the fourth leading cause of cancer-related death. Most patients present with an advanced stage of disease that has a dismal outcome, with a median survival of approximately 6 months. Evidently, there is a clear need for the development of new agents with novel mechanisms of action in this disease. A number of biological agents modulating different signal transduction pathways are currently in clinical development, inhibiting angiogenesis and targeting epidermal growth factor receptor, cell cycle, matrix metalloproteinases, cyclooxygenase-2, mammalian target of rapamycin, or proteasome. This is the first systematic review of the literature to synthesize all available data coming from trials and evaluate the efficacy and safety of molecular targeted drugs in unresectable and metastatic pancreatic cancer. However, it should be stressed that although multiple agents have been tested, only 9 phase 3 trials have been conducted and one agent (erlotinib) has been approved by the Food and Drug Administration for use in clinical practice. As knowledge accumulates on the molecular mechanisms underlying carcinogenesis in the pancreas, the anticipated development and assessment of molecularly targeted agents may offer a promising perspective for a disease which, to date, remains incurable.

Pancreatic cancer: why is it so hard to treat?

No common malignancy is as rapidly and inevitably fatal as pancreatic ductal adenocarcinoma (PDA). This grim fact has driven substantial research efforts into this disease in recent decades. Unfortunately, the investment has yet to result in a meaningful increase in 5-year survival. This has prompted many pancreatic cancer researchers and advocates to redouble their efforts, but also requires one to step back and ask why the previous efforts were lacking and to consider why pancreatic cancer is so difficult to treat. The difficulties are legion. PDA is characterized by an insidious clinical syndrome, but is rarely diagnosed at a time when surgical resection is feasible. We lack markers of early detection and screening programs remain unproven even in high risk populations. The location of the tumor in the retroperitoneum, the advanced age of patients, and the systemic effects of disease limit the options for local therapy. Chemotherapy may provide a small benefit, but most efforts to improve on the current regimens consistently and stubbornly fail in advanced clinical trials. The molecular and cellular features of ductal pancreatic tumors are aggressive and underlay multiple levels of therapeutic resistance. Non-cell-autonomous features including stromal proliferation, reduced vascular density and immune suppression also contribute to therapeutic resistance. Growing awareness of these the fundamental features of PDA has begun to guide ongoing research efforts. Clinical trials are now specifically targeting these tumor properties and actively focusing on the therapeutic implications of tumor stroma. As reviewed here, reflecting on the fundamental question of why pancreatic cancer is so difficult to treat is a necessary and informative exercise that will aid our efforts to improve patient outcomes. These efforts will lead to improvements in clinical trial design, expand our focus to include the molecular and histologic implications of novel treatment paradigms, and ultimately change the lives of our patients.

Potential clinical applications of matrix metalloproteinase inhibitors and their future prospects

Matrix metalloproteinases (MMPs) are endopeptidases that are involved in extracellular matrix degradation. They are also implicated in a number of abnormal bioprocesses, such as tumor growth, invasion, and metastasis. Therefore, controlling MMP activities has generated considerable interest as a possible therapeutic target. The tissue inhibitors of metalloproteinases (TIMPs) are the major naturally occurring proteins that specifically inhibit MMPs and assist in maintaining the balance between extracellular matrix destruction and formation. However, TIMPs are probably not suitable for pharmacological applications due to their short half-lives in vivo. During the last few decades, synthetic MMP inhibitors (MMPIs) have undergone rapid clinical development in attempts to control MMP enzymatic activities in abnormal bioprocesses. Although studies with these agents have met with limited clinical success, the field of MMPIs is still expanding, and generation of highly effective and selective MMPIs might be a promising direction of this research area.

The pancreas cancer microenvironment

Pancreatic ductal adenocarcinoma (PDA) is a common and lethal malignancy resulting in more than 250,000 deaths per year worldwide. Despite extensive efforts, cytotoxic and targeted therapies have provided only limited efficacy for patients with PDA to date. One contributing factor to the failure of systemic therapies may be the abundant tumor stromal content that is the characteristic of PDA. The PDA stroma, aptly termed the tumor microenvironment, occupies the majority of the tumor mass, and consists of a dynamic assortment of extracellular matrix components and nonneoplastic cells including fibroblastic, vascular, and immune cells. Recent work has revealed that the PDA stroma supports tumor growth and promotes metastasis and simultaneously serves as a physical barrier to drug delivery. Accordingly, methods that alter stromal composition or function, for instance interference with the vasculature via Notch/Hedgehog pathway inhibition or relief of vascular compression by hyaluronidase, are under active investigation. Here, we will review our current understanding of the PDA tumor microenvironment, and highlight opportunities for further exploration that may benefit patients.

Toward the goal of personalized therapy in pancreatic cancer by targeting the molecular phenotype

The purpose of this article is to provide a critical review of the molecular alterations in pancreatic cancer that are clinically investigated as therapeutic targets and their potential impact on clinical outcomes. Adenocarcinoma of exocrine pancreas is generally associated with poor prognosis and the conventional therapies are marginally effective. Advances in understanding the genetic regulation of normal and neoplastic development of pancreas have led to development and clinical evaluation of new therapeutic strategies that target the signaling pathways and molecular alterations in pancreatic cancer. Applications have begun to utilize the genetic targets as biomarkers for prediction of therapeutic responses and selection of treatment options. The goal of accomplishing personalized tumor-specific therapy with tolerable side effects for patients with pancreatic cancer is hopefully within reach in the foreseeable future.

Targeted destruction of the orchestration of the pancreatic stroma and tumor cells in pancreatic cancer cases: molecular basis for therapeutic implications

Pancreatic cancer is one of the most lethal malignancies, with a prominent desmoplastic reaction as its defining hallmark. The past several decades have seen dramatic progress in understanding of pancreatic cancer pathogenesis, including identification of precursor lesions, sequential transformation from normal pancreatic tissue to invasive pancreatic cancer and corresponding signature genetic events, and the biological impact of these events on malignant behavior. However, the currently used therapeutic strategies for epithelial tumor cells, which have exhibited potent antitumor activity in cell culture and animal models, have failed to produce significant effects in the clinic. The desmoplastic stroma surrounding pancreatic cancer cells, which accounts for about 90% of a tumor's mass, clearly is not a passive scaffold for cancer cells but an active contributor to carcinogenesis. Improved understanding of the dynamic interaction between cancer cells and the stroma will be important to designing effective therapeutic strategies for pancreatic cancer. This review focuses on the origin of stromal molecular and cellular components in pancreatic tumors, their biological effects on pancreatic cancer cells, and the orchestration of these two components.

Systemic therapies for pancreatic cancer--the role of pharmacogenetics

Effective systemic treatment of pancreatic cancer remains a major challenge, with progress hampered by drug resistance and treatment related toxicities. Currently available cytotoxic agents as monotherapy or in combination have provided only a modest survival benefit for patients with advanced disease. Disappointing phase III results with gemcitabine-based combinations in patients with advanced pancreatic cancer might be related to poor efficacy of systemic therapies in unselected patients. Future research strategies should prioritize identification of predictive markers through pharmacogenetic investigations. The individualization of patient treatment through pharmacogenetics may help to improve outcome by maximizing efficacy whilst lowering toxicity. This review provides an update on the pharmacogenetics of pancreatic cancer treatment and its influence on treatment benefits and toxicity.

Systemic therapies for pancreatic cancer--the role of pharmacogenetics

Effective systemic treatment of pancreatic cancer remains a major challenge, with progress hampered by drug resistance and treatment related toxicities. Currently available cytotoxic agents as monotherapy or in combination have provided only a modest survival benefit for patients with advanced disease. Disappointing phase III results with gemcitabine-based combinations in patients with advanced pancreatic cancer might be related to poor efficacy of systemic therapies in unselected patients. Future research strategies should prioritize identification of predictive markers through pharmacogenetic investigations. The individualization of patient treatment through pharmacogenetics may help to improve outcome by maximizing efficacy whilst lowering toxicity. This review provides an update on the pharmacogenetics of pancreatic cancer treatment and its influence on treatment benefits and toxicity.

The role of chemoradiation for patients with resectable or potentially resectable pancreatic cancer

Conflicting data and substantial controversy exist regarding optimal adjuvant treatment for those patients with resectable or potentially resectable adenocarcinoma of the pancreas. Despite improvements in short-term surgical outcomes, the use of newer chemotherapeutic agents, development of targeted agents and more precise delivery of radiation, the 5-year survival rates for early-stage patients remains less than 25%. This article critically reviews the existing data for various adjuvant treatment approaches for patients with surgically resectable pancreatic cancer. Our review confirms that despite several randomized clinical trials, the optimal adjuvant treatment approach for these patients remains unclear.

The novel ATR inhibitor VE-821 increases sensitivity of pancreatic cancer cells to radiation and chemotherapy

DNA damaging agents such as radiotherapy and gemcitabine are frequently used for the treatment of pancreatic cancer. However, these treatments typically provide only modest benefit. Improving the low survival rate for pancreatic cancer patients therefore remains a major challenge in oncology. Inhibition of the key DNA damage response kinase ATR has been suggested as an attractive approach for sensitization of tumor cells to DNA damaging agents, but specific ATR inhibitors have remained elusive. Here we investigated the sensitization potential of the first highly selective and potent ATR inhibitor, VE-821, in vitro. VE-821 inhibited radiation- and gemcitabine-induced phosphorylation of Chk1, confirming inhibition of ATR signaling. Consistently, VE-821 significantly enhanced the sensitivity of PSN-1, MiaPaCa-2 and primary PancM pancreatic cancer cells to radiation and gemcitabine under both normoxic and hypoxic conditions. ATR inhibition by VE-821 led to inhibition of radiation-induced G 2/M arrest in cancer cells. Reduced cancer cell radiosurvival following treatment with VE-821 was also accompanied by increased DNA damage and inhibition of homologous recombination repair, as evidenced by persistence of γH2AX and 53BP1 foci and inhibition of Rad51 foci, respectively. These findings support ATR inhibition as a novel approach to improve the efficacy and therapeutic index of standard cancer treatments across a large proportion of pancreatic cancer patients.

Anti-angiogenic drug discovery: lessons from the past and thoughts for the future

INTRODUCTION

Since the pioneering work of Judah Folkman, the discovery of bevacizumab has introduced the use of anti-angiogenic agents as a new modality for the treatment of cancer. Currently, hundreds of clinical trials involving anti-angiogenic agents, targeting different elements of the tumour angiogenesis pathway, are underway. However, thus far, the benefits of anti-angiogenic therapy in unselected patient populations are often marginal with harmful side effects.

AREAS COVERED

This article presents a detailed discussion of the lessons learnt from the use of bevacizumab and other VEGF pathway inhibitors in the clinical setting. Specifically, this article provides a review of the literature on anti-VEGF agents and other angiogenesis inhibitors used in pre-clinical and clinical trials for cancer treatment.

EXPERT OPINION

Future anti-angiogenic drug design centres on multiple protein targets and combinations including: growth factors, hypoxia-inducible factor and tumour endothelial cell markers unique to the tumour vasculature. Furthermore, treatment dosing, scheduling and combination with radiation and chemotherapy require further investigation, as does the potential of treating early disease, and the development of biomarkers which accurately predict response to therapy. These are essential for the future development of these drugs with individualised therapy likely to be the ultimate goal.

Stroma and pancreatic ductal adenocarcinoma: an interaction loop

Pancreatic ductal adenocarcinoma (PDA) has two exceptional features. First, it is a highly lethal disease, with a median survival of less than 6 months and a 5-year survival rate less than 5%. Second, PDA tumor cells are surrounded by an extensive stroma, which accounts for up to 90% of the tumor volume. It is well recognized that stromal microenvironment can accelerate malignant transformation, tumor growth and progression. More importantly, the interaction loop between PDA and its stroma greatly contributes to tumor growth and progression. We propose that the extensive stroma of PDA is closely linked to its poor prognosis. An improved understanding of the mechanisms that contribute to pancreatic tumor growth and progression is therefore urgently needed. Targeting the stroma may thus provide novel prevention, earlier detection and therapeutic options to this deadly malignancy. Accordingly, in this review, we will summarize the mechanism of PDA stroma formation, the role of the stroma in tumor progression and therapy resistance and the potential of stroma-targeted therapeutics strategies.

Increased invasiveness of MMP-9-deficient tumors in two mouse models of neuroendocrine tumorigenesis

Despite their apparent success in pre-clinical trials, metalloproteinase (MMP) inhibitors proved to be inefficacious in clinical settings. In an effort to understand the underlying causes of this unanticipated outcome, we modeled the consequences of long-term MMP inhibition by removing one of the major players in tumorigenesis, MMP9, in two complimentary mouse models of pancreatic neuroendocrine carcinogenesis: Myc;BclXl and RIP1-Tag2. By employing gel zymography and a fluoregenic solution assay, we first established that MMP9 is expressed and activated in Myc;BclXl tumors in an interleukin-1β-dependent manner. The genetic deletion of MMP9 in Myc;BclXl mice impairs tumor angiogenesis and growth analogous to its absence in the RIP1-Tag2 model. Notably, tumors that developed in the context of MMP9-deficient backgrounds in both models were markedly more invasive than their typical wild-type counterparts, and expressed elevated levels of pro-invasive cysteine cathepsin B. The increased invasion of MMP9-deficient tumors was associated with a switch in the spectrum of inflammatory cells at the tumor margins, involving homing of previously undetected, cathepsin-B expressing CD11b;Gr1-positive cells to the invasive fronts. Thus, plasticity in the tumor inflammatory compartment is partially responsible for changes in the expression pattern of tumor-associated proteases, and may contribute to the compensatory effects observed on MMP inhibition, hence accounting for the heightened tumor progression described in late stage clinical trials.

Pancreatic cancer: medical management (novel chemotherapeutics)

Pancreatic adenocarcinoma is the fourth leading cause of cancer death and has an extremely poor prognosis: The 5-year survival probability is less than 5% for all stages. The only chance for cure or longer survival is surgical resection; however, only 10% to 20% of patients have resectable disease. Although surgical techniques have improved, most who undergo complete resection experience a recurrence. Adjuvant systemic therapy reduces the recurrence rate and improves outcomes. There is a potential role for radiation therapy as part of treatment for locally advanced disease, although its use in both the adjuvant and neoadjuvant settings remains controversial. Palliative systemic treatment is the only option for patients with metastatic disease. To date, however, only the gemcitabine plus erlotinib combination, and recently the FOLFIRINOX regimen, have been associated with relatively small but statistically significant improvements in OS when compared directly with gemcitabine alone. Although several meta-analyses have suggested a benefit associated with combination chemotherapy, whether this benefit is clinically meaningful remains unclear, particularly in light of the enhanced toxicity associated with combination regimens. There is growing evidence that the exceptionally poor prognosis in PC is caused by the tumor's characteristic abundant desmoplastic stroma that plays a critical role in tumor cell growth, invasion, metastasis, and chemoresistance. Carefully designed clinical trials that include translational analysis will provide a better understanding of the tumor biology and its relation to the host stromal cells. Future directions will involve testing of new targeted agents, understanding the pharmacodynamics of our current targeted agents, searching for predictive and prognostic biomarkers, and exploring the efficacy of different combinations strategies.

[Chemotherapy of metastatic pancreatic adenocarcinoma: challenges and encouraging results]

The outcome for patients with metastatic pancreatic ductal adenocarcinoma is dismal. In this article, we will review current first-line treatments for metastatic pancreatic adenocarcinoma focusing on phase III randomized studies. Single-agent gemcitabine, the reference treatment since 1995, offers only slight benefit. Numerous trials using gemcitabine in combination with different cytotoxic agents have resulted in no major improvement compared to gemcitabine alone. Only the gemcitabine-erlotinib combination has shown a small, but statistically improvement in survival. In selected patients with good performance status ECOG 0-1, no cardiac ischemia and almost normal bilirubin level, the Folfirinox regimen, when compared to gemcitabine as single agent, was associated with more toxicities, but also with significant increased survival and delay in the degradation of quality of life. So, Folfirinox is a new more toxic and more efficient regimen that may be considered in patients with good performance status.

Does health-related quality of life improve for advanced pancreatic cancer patients who respond to gemcitabine? Analysis of a randomized phase III trial of the cancer and leukemia group B (CALGB 80303)

CONTEXT

Gemcitabine for advanced pancreatic cancer (APC) is palliative and the prognosis is poor, making health-related quality of life (HRQOL) particularly important.

OBJECTIVES

We evaluated HRQOL with the EuroQol (EQ-5D™) in patients with APC participating in Cancer and Leukemia Group B 80303, a multicenter, double-blind, randomized trial comparing overall survival (OS) between two treatment arms: gemcitabine with bevacizumab or gemcitabine with placebo.

METHODS

A consecutive subsample of patients was invited to complete the EQ-5D surveys. Because neither clinical nor HRQOL outcomes differed based on the study arm, analyses were pooled. Changes in mean scores from baseline to eight weeks and the prognostic value of the EQ-5D were evaluated.

RESULTS

Mean index scores remained stable (0.78 at baseline [n=267], 0.79 at eight weeks [n=186], P=0.34, Wilcoxon signed rank test), attributable to a modest deterioration of physical function domain scores coincident with small improvements in pain and anxiety/depression scores. A small decline in visual analogue scale scores was observed (70.7 vs. 68.2, P=0.026). HRQOL changes within chemotherapy response strata revealed stable index scores but a trend of worsened physical function among patients with disease progression compared with those with stable or improved disease. Visual analogue scale scores trended downward over time irrespective of chemotherapy response status, with a statistically meaningful deterioration in patients who progressed (68.9 vs. 64.4, P=0.029). Baseline scores from both EQ-5D scales were significant predictors of OS in Cox proportional hazard models.

CONCLUSION

Response to gemcitabine treatment in APC is not associated with appreciable improvement of global HRQOL. Small improvements in pain and mood are observed despite progressive functional decline. Those who respond to gemcitabine may experience a slight slowing of functional deterioration.

Current knowledge on pancreatic cancer

Pancreatic cancer is the fourth leading cause of cancer death with a median survival of 6 months and a dismal 5-year survival rate of 3-5%. The development and progression of pancreatic cancer are caused by the activation of oncogenes, the inactivation of tumor suppressor genes, and the deregulation of many signaling pathways. Therefore, the strategies targeting these molecules as well as their downstream signaling could be promising for the prevention and treatment of pancreatic cancer. However, although targeted therapies for pancreatic cancer have yielded encouraging results in vitro and in animal models, these findings have not been translated into improved outcomes in clinical trials. This failure is due to an incomplete understanding of the biology of pancreatic cancer and to the selection of poorly efficient or imperfectly targeted agents. In this review, we will critically present the current knowledge regarding the molecular, biochemical, clinical, and therapeutic aspects of pancreatic cancer.

Continuous transarterial infusion chemotherapy with gemcitabine and 5-Fluorouracil for advanced pancreatic carcinoma

PURPOSE

Pancreatic carcinoma is one of the most malignant tumors of the alimentary system, with relatively high incidence rates. The purpose of this study was to assess the efficacy and safety of two regimens for advanced pancreatic carcinoma: continuous transarterial infusion versus systemic venous chemotherapy with gemcitabine and 5-fluorouracil.

METHODS

Of the 48 patients with advanced pancreatic carcinoma receiving chemotherapy with gemcitabine and 5-fluorouracil, 24 received the selective transarterial infusion, and 24 the systemic chemotherapy. For the continuous transarterial infusion group (experimental group), all patients received gemcitabine 1000 mg/m2,given by 30-minute transarterial infusion, on day 1 of a 4-week cycle for 2 cycles, and a dose of 600 mg/ m2 5-fluorouracil was infused on days 1~5 of a 4-week cycle for 2 cycles. For the systemic venous group (control group), gemcitabine and 5-fluorouracil were infused through a peripheral vein, a dose of 1000 mg/m2 gemcitabine being administrated over 30 min on days 1 and 8 of a 4-week cycle for 2 cycles, and a dose of 600 mg/m2 5-fluorouracil was infused on days 1~5 of a 4-week cycle for 2 cycles. The effectiveness and safety were evaluated after 2 cycles according to WHO criteria.

RESULTS

The objective effective rate in transarterial group was 33.3% versus 25% in the systemic group, the difference not being significant (P=0.626). Clinical benefit rates(CBR) in the transarterial and systemic groups were 83.3% and 58.3%, respectively (P=0.014). The means and medians for survival time in transarterial group were higher than those of the systemic group (P<0.005). at the same time, the adverse effects did not significantly differ between the two groups (P>0.05).

CONCLUSION

Continuous transarterial infusion chemotherapy with gemcitabine and 5-fluorouracil could improve clinical benefit rate and survival time of patients with advanced pancreatic carcinoma, compared with systemic venous chemotherapy. Since adverse effects were limited in the transarterial group, the regimen of continuous transarterial infusion chemotherapy can be used more extensively in clinical practice. A CT and MRI conventional sequence can be used for efficacy evaluation after chemotherapy in pancreatic carcinoma.

Matrix metalloproteinases in tumorigenesis: an evolving paradigm

Proteases are crucial for development, tissue remodeling, and tumorigenesis. Matrix metalloproteinases (MMPs) family, in particular, consists of more than 20 members with unique substrates and diverse function. The expression and activity of MMPs in a variety of human cancers have been intensively studied. MMPs have well-recognized roles in the late stage of tumor progression, invasion, and metastasis. However, increasing evidence demonstrates that MMPs are involved earlier in tumorigenesis, e.g., in malignant transformation, angiogenesis, and tumor growth both at the primary and metastatic sites. Recent studies also suggest that MMPs play complex roles in tumor progression. While most MMPs promote tumor progression, some of them may protect the host against tumorigenesis in a context-dependent manner. MMPs have been chosen as promising targets for cancer therapy on the basis of their aberrant up-regulation in malignant tumors and their ability to promote cancer metastasis. Although preclinical studies testing the efficacy of MMP suppression in tumor models were so encouraging, the results of clinical trials in cancer patients have been rather disappointing. Here, we review the complex roles of MMPs and their endogenous inhibitors such as tissue inhibitors of metalloproteinase in tumorigenesis and strategies in suppressing MMPs.

Looking to the future: biomarkers in the management of pancreatic adenocarcinoma

The incidence and mortality of pancreas cancer converge. There has been little advancement in the treatment of pancreas cancer since the acceptance of gemcitabine as the standard therapy. Unfortunately, the efficacy of gemcitabine is dismal. While there is much discussion for the development of biomarkers to help direct therapy in this area, there is little action to move them into clinical practice. Herein, we review potential pancreatic cancer biomarkers and discuss the limitations in their implementation.

A phase 2 study of oral MKC-1, an inhibitor of importin-β, tubulin, and the mTOR pathway in patients with unresectable or metastatic pancreatic cancer

BACKGROUND

MKC-1 is an orally available cell cycle inhibitor with downstream targets that include tubulin and the importin-β family. We conducted an open-label Phase II study with MKC-1 in patients with advanced pancreatic cancer.

METHODS

Eligibility criteria included unresectable or metastatic pancreatic cancer, performance status of 1 or better, and failure of at least one prior regimen of chemotherapy. MKC-1 was administered orally, twice daily, initially at 100 mg/m(2) dosing for 14 consecutive days of a 28-day cycle. This schedule was modified during the trial to fixed and continuous dosing of 150 mg per day.

RESULTS

20 of an original target of 33 patients were accrued, with a median age of 61 (range 44-81). No objective responses were observed, with one patient demonstrating stable disease. Overall survival was 101 days from the start of MKC-1 administration, and median time to progression was 42 days. The most common adverse events listed as related or possibly related to MKC-1 administration were hematologic toxicities and fatigue. One patient developed grade 5 (fatal) pancytopenia. Grade 3 and 4 events included cytopenias (lymphopenia, anemia), hyperbilirubinemia, pneumonia, mucositis, fatigue, infusion reaction, anorexia, and hypoalbuminemia.

CONCLUSIONS

MKC-1 administration was associated with substantial toxicity and did not demonstrate sufficient activity in patients with advanced pancreatic cancer to justify further exploration in this patient population.

Dose-intense PEFG (cisplatin, epirubicin, 5-fluorouracil, gemcitabine) in advanced pancreatic adenocarcinoma: a dose-finding study

The aim of this study was to assess the maximum tolerated dose (MTD) of an intensified PEFG regimen administered every 14 days to patients with Stage III or metastatic pancreatic adenocarcinoma. Twenty-nine patients received fixed doses of both epirubicin (30 mg/m2) and 5-fluorouracil (200 mg/m2/day on Days 1-14) and of escalating doses of cisplatin and gemcitabine. The MTD was cisplatin 30 mg/m2 and gemcitabine 800 mg/m2. With respect to classical PEFG, intensified regimen potentially improved the dose-intensity of both cisplatin and epirubicin by 50 percent and of gemcitabine by 33 percent, reduced Grade 3-4 haematological toxicity and the number of outpatient accesses.

Medical treatment of pancreatic cancer: new hopes after 10 years of gemcitabine

Exocrine pancreatic cancer has a very poor prognosis. R0 resection of the tumor is to date the only potentially curative approach, but less than 20% of patients are eligible for a curative surgery at diagnosis. Until recently, gemcitabine was the standard treatment for advanced and metastatic pancreatic cancer patients, since it was shown more than a decade ago to induce clinical benefit and to improve survival when compared to weekly bolus 5-fluorouracil. In order to improve patients' outcome many trials have, during the last 10 years, explored the pharmacokinetic modulation of gemcitabine and combination therapies with gemcitabine and other anti-cancer agents with consistent negative results. It is finally a trial assessing the efficacy of a combination chemotherapy without gemcitabine: the FOLFIRINOX regimen, reported this year, that has shown for the first time a significant improvement in progression free and overall survivals. In parallel, many trials testing new targeted agents in these patients are currently ongoing. After 10 years without significant progress in the treatment of pancreatic cancer patients, the hope that a significant improvement in the outcome of these patients can be achieved has been raised.

Prognostic implications of intraoperative radiotherapy for unresectable pancreatic cancer

BACKGROUND/AIMS

To assess the prognostic effect of intraoperative radiotherapy (IORT) in unresectable pancreatic cancer.

METHODS

We reviewed 198 patients with unresectable pancreatic cancer, which was found during experimental laparotomy. Liver metastasis was observed in 70 patients, peritoneal metastasis in 44, liver and peritoneal metastasis in 23 and locally advanced tumor in 61. Treatment consisted of IORT with or without postoperative chemotherapy. Overall survival (OS) and prognostic factors were evaluated for each pattern of disease spread.

RESULTS

IORT was performed in 120 patients, and chemotherapy was administered in 80. Sixty patients did not receive either treatment. OS in the untreated group was significantly inferior to that for IORT alone and IORT plus gemcitabine (GEM)-based chemotherapy. IORT and GEM-based chemotherapy were identified as independent prognostic factors [hazard ratio (HR) = 0.51, p < 0.001; HR = 0.43, p < 0.001]. IORT was an independent prognostic determinant for patients with peritoneal metastasis (HR = 0.24, p = 0.011) but not for those with liver metastasis (HR = 0.78, p = 0.381).

CONCLUSION

IORT followed by GEM-based chemotherapy is the recommended treatment strategy in unresectable pancreatic cancer. and IAP.

Salvage therapy with mitomycin and ifosfamide in patients with gemcitabine-resistant metastatic pancreatic cancer: a phase II trial

BACKGROUND

At the time of upfront treatment failure, over half of the patients with advanced pancreatic cancer are candidates for further treatment.

METHODS

Patients with metastatic gemcitabine-resistant pancreatic cancer were treated with mitomycin 8 mg/m(2) on day 1, ifosfamide 2,500 mg/m(2) and mesna 3,000 mg/m(2) on days 1-3 every 28 days until progressive disease. A positive responder was defined as a patient who was progression free at 6 months from trial enrollment. According to the Fleming design, a sample size of 34 patients was estimated assuming p0 = 0.05 and p1 = 0.20.

RESULTS

Between May 2006 and December 2007, 21 patients (median age 56 years; median Karnofsky performance score 80) were enrolled. One patient died before receiving any treatment. Eighteen patients interrupted chemotherapy due to progressive disease (n = 15), toxicity (n = 2) or refusal (n = 1). Grade >2 toxicity consisted of neutropenia in 80% of patients, thrombocytopenia and fatigue in 20% and anemia in 10%. Only 1 patient was progression free at 6 months (5%). One patient had a partial response (5%) and 2 patients had stable disease (10%). Median survival was 3.7 months.

CONCLUSION

Based on the poor outcome observed and on the high level of grade 3-4 toxicity, the trial was prematurely stopped and the mitomycin and ifosfamide regimen was considered insufficiently active in gemcitabine-pretreated advanced pancreatic cancer.

Targeting metastatic upper gastrointestinal adenocarcinomas

Upper gastrointestinal (GI) tumors, including adenocarcinoma of the esophagus, stomach, pancreas, and biliary tree, have traditionally been difficult to treat with cytotoxic chemotherapeutic agents. There has been little drug development success in treating these cancers over the last 20 years, perhaps a reflection of a combination of the aggressive biology of these tumors, the void in effective and specific drug development for these varied tumors, and the lack of properly designed, biologically-based clinical trials. Recently, so called "targeted agents" have risen to the forefront in the care of cancer patients and have made strong impacts in many areas of oncology, particularly gastrointestinal stromal tumors (GIST), colon, breast, and lung cancers. Unfortunately, slow progress has been made using such agents in upper GI tumors. However, more recently, trials in some tumor types have demonstrated gains in progression free survival and overall survival. In this review, we discuss the drugs and pathways that have been most successful in the treatment of upper GI tumors and present the relevant data supporting their use for each tumor site. Additionally, we will explore a few novel pathways that may prove effective in the treatment of upper GI malignancies in the near future.

Treatment trends in metastatic pancreatic cancer patients: Is it time to change?

BACKGROUND

Since gemcitabine became the standard treatment for metastatic pancreatic adenocarcinoma, combination chemotherapy obtained conflicting impact on survival (OS).

AIMS

To evaluate Italian treatment trends in metastatic pancreatic cancer.

METHODS

Data on treatment outcome of 943 chemo-naive patients with pathological diagnosis of stage IV pancreatic adenocarcinoma treated between 1997 and 2007 in Italian centres were analysed.

RESULTS

Four treatment groups could be identified: (1) single agent gemcitabine (N=529); (2) gemcitabine-platinating agent doublets (N=105); (3) gemcitabine-free three-drug intraarterial combination (N=75); (4) four-drug gemcitabine-cisplatin-fluoropyrimidine based combinations (N=170). Median and actuarial 1 y OS of the whole population were 6.2 months and 20%, respectively. Gemcitabine (median OS 5.1 months) appeared significantly inferior to gemcitabine-free triplets (median OS 6.0 months; p=.04), gemcitabine-platinating agent doublets (median OS 7.4 months; p=.00001), or gemcitabine-based four drug combinations (median OS 9.1 months; p<.00001).

CONCLUSION

These data mirror the Italian clinical practice in the therapeutic management of pancreatic cancer and suggest that four-drug combination chemotherapy may be included amongst the candidate regimens for phase III testing.

Phase II study of erlotinib plus gemcitabine in Japanese patients with unresectable pancreatic cancer

Erlotinib combined with gemcitabine has not been evaluated in Japanese patients with unresectable pancreatic cancer. This two-step phase II study assessed the safety and pharmacokinetics of erlotinib 100 mg/day (oral) plus gemcitabine 1000 mg/m(2) (i.v. days 1, 8, 15) in a 28-day cycle in the first step, and efficacy and safety in the second step. The primary end-point was safety. One hundred and seven patients were enrolled (first step, n = 6; second step, n = 101). The most common adverse event was RASH (compiled using the preferred terms rash, acne, exfoliative rash, dermatitis acneiform, erythema, eczema, dermatitis and pustular rash) in 93.4% of patients. One treatment-related death occurred. While interstitial lung disease-like events were reported in nine patients (8.5%; grade 1/2/3, 3.8/2.8/1.9%), all patients recovered or improved. The median overall survival, the 1-year survival rate and median progression-free survival were 9.23 months, 33.0% and 3.48 months, respectively. The overall response and disease control rates were 20.3% and 50.0%, respectively. In Japanese patients with unresectable pancreatic cancer, erlotinib plus gemcitabine had acceptable toxicity and efficacy that was not inferior to that seen in Western patients.

A phase I/II study of the Src inhibitor saracatinib (AZD0530) in combination with gemcitabine in advanced pancreatic cancer

AIM

This phase I/II study of saracatinib in combination with gemcitabine in patients with advanced pancreatic cancer was conducted by the NCIC Clinical Trials Group. The aims were to define the recommended phase II dose (RP2D) of saracatinib when combined with gemcitabine, and assess the efficacy of this combination in advanced pancreatic cancer.

PATIENTS AND METHODS

Eligibility criteria included locally advanced or metastatic pancreatic adenocarcinoma and no prior chemotherapy. In phase I saracatinib was escalated in combination with gemcitabine (1000 mg/m(2)) to determine the recommended phase II dose (RP2D). The study was then expanded to a single arm phase II trial using a Simon 2-stage design. The primary endpoint was objective tumor response (OR) plus stable disease ≥ 4 months (SD4) rate; if ≥ 8 patients had OR+SD4, the study would proceed to stage 2.

RESULTS

Thirteen patients were enrolled into the phase I portion of this study. Saracatinib 175 mg PO daily was chosen as the RP2D in combination with gemcitabine. Twenty-one additional patients were then enrolled at the RP2D (phase II). Of the 22 response evaluable patients treated at the RP2D, 9 patients (40.9%) had progressive disease, 6 patients (27.3%) had stable disease for less than 4 months, 5 patients (22.7%) had SD4, and 2 patients (9.1%) had a partial response to treatment. Objective criteria for continuing to stage 2 were thus not met and the trial was closed following the accrual of 34 patients.

CONCLUSION

Saracatinib 175 mg daily in combination with gemcitabine is well tolerated but the combination did not improve efficacy over what would be expected from gemcitabine alone.

Management of mucinous cystic neoplasms of the pancreas

The purpose of this study was to investigate the actual management of mucinous cystic neoplasm (MCN) of the pancreas. A systematic review was performed in December 2009 by consulting PubMed MEDLINE for publications and matching the key words “pancreatic mucinous cystic neoplasm”, “pancreatic mucinous cystic tumour”, “pancreatic mucinous cystic mass”, “pancreatic cyst”, and “pancreatic cystic neoplasm” to identify English language articles describing the diagnosis and treatment of the mucinous cystic neoplasm of the pancreas. In total, 16 322 references ranging from January 1969 to December 2009 were analysed and 77 articles were identified. No articles published before 1996 were selected because MCNs were not previously considered to be a completely autonomous disease. Definition, epidemiology, anatomopathological findings, clinical presentation, preoperative evaluation, treatment and prognosis were reviewed. MCNs are pancreatic mucin-producing cysts with a distinctive ovarian-type stroma localized in the body-tail of the gland and occurring in middle-aged females. The majority of MCNs are slow growing and asymptomatic. The prevalence of invasive carcinoma varies between 6% and 55%. Preoperative diagnosis depends on a combination of clinical features, tumor markers, computed tomography (CT), magnetic resonance imaging, endoscopic ultrasound with cyst fluid analysis, and positron emission tomography-CT. Surgery is indicated for all MCNs.

Human Equilibrative Nucleoside Transporter 1 (hENT1) in Pancreatic Adenocarcinoma: Towards Individualized Treatment Decisions

Pancreatic cancer is one of the most lethal cancers, where curative surgical resections are rare and less than 5% of patients experience long-term survival. Despite numerous clinical trials, improvements in the systemic treatment of this disease have been limited. Gemcitabine, a nucleoside analogue, is still considered the standard of care chemotherapy for most patients in the advanced disease setting. To exert its cytotoxic effects, gemcitabine must enter cells via nucleoside transporters, most notably human equilibrative nucleoside transporter 1 (hENT1). Increasingly strong evidence suggests hENT1 is a prognostic biomarker in gemcitabine-treated pancreatic cancer, and may well be a predictive biomarker of gemcitabine efficacy. In this review, we synthesize the literature surrounding hENT1 in pancreatic cancer, identify the key outstanding questions, and suggest strategies to prospectively evaluate the clinical utility of hENT1 in future clinical studies.

The molecular targets for the diagnosis and treatment of pancreatic cancer

Pancreatic cancer is considered an aggressive malignancy that responds poorly to current treatments and therefore has a dismal survival rate. This disease is usually not diagnosed until a late stage, at which point palliative chemotherapy with the purine analogue gemcitabine and/or a fluoropyrimidine or a platinum agent is the standard approach. There are some new data on the molecular and genetic changes that take place in pancreatic cancer, which may facilitate the accuracy of diagnosis and efficacy of treatments. However, translational efforts in clinical practice have increased clinicians' options with a targeted agent, erlotinib, in combination with the standard gemcitabine chemotherapy. Many other novel drugs currently being tested in the field of pharmaco-oncology target various altered biological pathways and molecules. Nevertheless, the lack of clinically significant improvements in treatments is rendering efforts to develop methods of early diagnosis both more urgent and promising. The aim of this review was to summarize the molecular basis of pancreatic carcinogenesis and the latest developments in diagnosis by molecular means, focusing on the results of clinical research into targeted and personalized treatments.