Downregulation of GSTM2 enhances gemcitabine chemosensitivity of pancreatic cancer in vitro and in vivo

Glutathione-S-transferases (GSTs) not only show cytoprotective role and their involvement in the development of anticancer drug resistance, but also transmit signals that control cell proliferation and apoptosis. However, the role of GST isoforms in chemotherapy resistance remains elusive in pancreatic cancer. Here, we demonstrated that gemcitabine treatment increased the GSTM2 expression in pancreatic cancer cell lines. Knockdown of GSTM2 by siRNA elevated apoptosis and decreased viability of pancreatic cancer cells treated with gemcitabine. Moreover, in vivo experiments further showed that shRNA induced GSTM2 downregulation enhanced drug sensitivity of gemcitabine in orthotopic pancreatic tumor mice. We also found that GSTM2 levels were lower in tumor tissues than in non-tumor tissues and higher GSTM2 expression was significantly associated with longer overall survival. In conclusion, our findings indicate that GSTM2 expression is essential for the survival of pancreatic cancer cells undergoing gemcitabine treatment and leads to chemo resistance. Downregulation of GSTM2 in pancreatic cancer may benefit gemcitabine treatment. GSTM2 expression in patients also shows significant correlation with overall survival. Thus, our study suggests that GSTM2 is a potential target for chemotherapy optimization and prognostic biomarker of pancreatic cancer.     

STAT3基因沉默对胰腺癌细胞株的增殖及对吉西他滨敏感性的影响

目的 探讨信号转导与转录激活因子3（STAT3）基因沉默对吉西他滨介导的胰腺癌细胞株增殖和凋亡及对吉西他滨治疗敏感性的影响.方法 以STAT3荧光素慢病毒及对照的海肾萤光素酶慢病毒感染6株胰腺癌细胞株（BxPC3、L3.6pl、CFPAC-1、MPanc-96,PANC1、MiaPaCa-2）及人胰腺癌导管上皮细胞株（HPDE）,检测各细胞STAT3及磷酸化STAT3（pSTAT3）蛋白的表达.应用RNA干扰技术沉默6株胰腺癌细胞株STAT3基因表达,应用蛋白质印迹法检测细胞STAT3蛋白表达,MTS法检测细胞的增殖,流式细胞仪检测细胞的凋亡.结果 6株胰腺癌细胞株STAT3及pSTAT3蛋白表达量均显著高于HPDE细胞,但胰腺癌细胞的表达量与其对吉西他滨耐药性及敏感性无明显相关.转染靶向STAT3的siRNA（siSTAT3）的BxPC3、MiaPaCa-2、PANC1、L3.6pl、CFPAC-1、MPanc-96细胞STAT3蛋白表达量分别为0.40±0.04、0.09±0.01、0.38±0.02、0.27 ±0.06、0.10±0.02、0.24±0.04,较转染阴性对照siRNA（siNC）细胞的表达量2.27±0.21、1.83 ±0.12、2.27±0.17、2.23±0.21、0.33±0.05、1.24±0.19均显著下降（P值均＜0.05）.但对细胞的增殖及凋亡无明显影响.STAT3基因沉默可以增加所有6株细胞对吉西他滨的敏感性,吉西他滨的杀伤效应增加了10％～15％.结论 STAT3表达水平同胰腺癌的化疗药物耐药性无明显相关性,沉默STAT3基因表达可增加细胞对吉西他滨耐治疗的敏感性.     

B7H4, HSP27 and DJ-1 molecular markers as prognostic factors in pancreatic cancer

ObjectivesPancreatic cancer (PC) is one of the most lethal tumors of the gastrointestinal tract. The ability to predict which patients would benefit most from surgical intervention and chemotherapy would be a great clinical tool. A large number of potential markers have been identified lately in pancreatic cancer and their clinical utilities as prognostic tools are under investigation.MethodsWe recruited 41 patients who had undergone radical surgical resection for PC between 2003 and 2010. To investigate the prognostic factors, we evaluated 3 possible markers: B7H4, HSP27 and DJ-1 protein expressions in the tissue specimens of these 41 patients by immunohistochemistry and analyzed the clinical and pathological features of these specimens.ResultsThe expression of the three antigens was independently associated with a negative impact of chemotherapy with gemcitabine on patient's survival. Moreover, patients who overexpressed B7H4 had worse prognosis than the ones who did not.ConclusionsB7H4, DJ-1 and HSP27 may be used in the future as prognostic markers that express resistance of pancreatic cancer patients to chemotherapy with gemcitabine.     

Involvement of microRNA-181b in the gemcitabine resistance of pancreatic cancer cells

Background/objectivesMicroRNAs (miRs) have been shown to regulate the sensitivity to several chemotherapeutic agents in various types of cancers. MiR-181b is one of such regulators, yet its importance in pancreatic cancer is not determined so far. The aim of this study was to investigate the relationship between microRNA (miR)-181b expression and gemcitabine resistance in pancreatic cancer cells.MethodsThe effects of overexpression or knockdown of miR-181b on four pancreatic cancer cell lines exposed to gemcitabine were examined. The induction of apoptosis and the changes of the cylindromatosis (CYLD) protein were examined. Furthermore, the effect of small interference RNA for CYLD (siCYLD) on cell viability and the relationship between CYLD and nuclear factor kappa B (NF-κB) were investigated.ResultsThe expression of miR-181b was higher in BxPC3, Panc1 and PSN1 cells compared with MiaPaCa2 cells. Pre-miR-181b transfection into MiaPaCa2 cells increased their gemcitabine resistance, whereas anti-miR-181b transfection into the other pancreatic cancer cell lines reduced their resistance to gemcitabine and led to the induction of apoptosis. The protein levels of CYLD were increased by anti-miR-181b in Panc1 and PSN1 cells. Inhibition of CYLD increased the NF-κB activity and gemcitabine resistance in Panc1 and PSN1 cells.ConclusionsThe present study demonstrated that miR-181b was associated with the resistance of pancreatic cancer cells to gemcitabine, and verified that miR-181b enhances the activity of NF-κB by inhibiting CYLD, leading to the resistance to gemcitabine. Our results suggest that miR-181b is a potential target for decreasing gemcitabine resistance.     

Human equilibrative nucleoside transporter 1 (hENT1): Do we really have a new predictive biomarker of chemotherapy outcome in pancreatic cancer patients?

Although systemic chemotherapy significantly improves the overall survival of pancreatic cancer patients, the prognosis remains extremely poor. The development of a drug resistance, either de novo or induced resistance, significantly limits the effectiveness of chemotherapy. SLC29A1 gene encodes human equilibrative nucleoside transporter 1 (hENT1) protein that is mediating the transport of nucleotides, both purines and pyrimidines, into the tumor cells. The aim of this mini-review is to summarize the current information concerning the prognostic and predictive role of SLC29A1 transporter (hENT1) expression in pancreatic cancer. Increased expression of SLC29A1 in vitro has been described as a potential critical factor determining the sensitivity of pancreatic cancer cells to gemcitabine and 5-fluorouracil, the principal cytotoxic agents used in the treatment of pancreatic cancer. The reports on the relationship between SLC29A1 expression and prognosis of patients with pancreatic cancer are currently rather conflicting. However, majority of studies on patients with resected pancreatic cancer have suggested that high SLC29A1expression may be predictive of improved survival in patients treated with gemcitabine. SLC29A1 has not been shown to represent a predictive biomarker for patients treated by 5-fluorouracil. In conclusion, potential prognostic and predictive role of SLC29A1 has been demonstrated for selected subset of patients.     

Oncogenic ADAM28 induces gemcitabine resistance and predicts a poor prognosis in pancreatic cancer

BACKGROUND Pancreatic cancer is a major cause of cancer-related death, with a 5-year overall survival rate being below 5%. The main causes of poor prognosis in pancreatic cancer include easy metastasis, high recurrence rate, and robust drug resistance.Gemcitabine is a first-line drug for patients with unresectable pancreatic cancer.However, due to drug resistance, the clinical effect is not satisfactory. ADAM28 is reported as a tumor promoter in some cancers, but its role in pancreatic cancer and gemcitabine chemoresistance in pancreatic cancer has not been elucidated.AIM To identify if ADAM28 can act as an important target to reverse the gemcitabine drug resistance in pancreatic cancer.METHODS RNA-sequence analysis was applied to explore the potential targets involved in the gemcitabine of pancreatic cancer. SW1990 pancreatic cancer cells were treated with an increased dose of gemcitabine, and the mRNA levels of ADAM28 were evaluated by RT-PCR. The protein and mRNA levels of ADAM28 were confirmed in the gemcitabine resistant and parallel SW1990 cells. The ADAM28 expression was also assessed in TCGA and GEO databases, and the results were confirmed in the collected tumor and adjacent normal tissues. The overall survival(OS) rate and relapse-free survival(RFS) rate of pancreatic cancer patients with high ADAM28 level and low ADAM28 level in TCGA were evaluated with Kaplan-Meier Plotter. Furthermore, the OS rate was calculated in pancreatic cancer patients with high tumor mutation burden(TMB) and low TMB. CCK-8 assay was used to examine the effect of ADAM28 on the viability ofSW1990 cells. The ADAM28 and its co-expressed genes were analyzed in the cBioPortal for cancer genomics and subjected to GSEA pathway analysis. The correlations of ADAM28 with GSTP1, ABCC1, GSTM4, and BCL2 were analyzed based on TCGA data on pancreatic cancer.RESULTS RNA-sequence analysis identified that ADAM28 was overexpressed in gemcitabine-resistant cells, and gemcitabine treatment could induce the expression of ADAM28. The mRNA and protein levels of ADAM28 were elevated in gemcitabine-resistant SW1990 cells compared with parallel cells. Also,the expression of ADAM28 was upregulated in pancreatic tumor tissues against normal pancreatic tissues. Notably, ADAM28 was highly expressed in the classical type than in the basal tumor type. Furthermore, the high expression of ADAM28 was associated with low OS and RFS rates. Interestingly, the high levels of ADAM28 was associated with a significantly lower OS rate in the high TMB patients, but not in the low TMB patients. Moreover, overexpression of ADAM28 could reduce the cell viability inhibition by gemcitabine, and knockdown of ADAM28 could enhance the proliferation inhibition by gemcitabine. The GSEA analysis showed that ADAM28 was related to the regulation of drug metabolism, and ADAM28 was significantly positively correlated with GSTP1, ABCC1, GSTM4, and BCL2.CONCLUSION This study demonstrates that ADAM28 is overexpressed in pancreatic cancer,and closely involved in the regulation of gemcitabine resistance. Overexpression of ADAM28 is a novel prognostic biomarker in pancreatic cancer.     

Human equilibrative nucleoside transporter 1 level does not predict prognosis in pancreatic cancer patients treated with neoadjuvant chemoradiation including gemcitabine

Background

Gemcitabine is a key drug for the treatment of pancreatic cancer. Human equilibrative nucleoside transporter 1 (hENT1) is a major transporter responsible for gemcitabine uptake into cells. This study was conducted to elucidate the association between expression level of hENT1 and outcome for pancreatic cancer patients treated with neoadjuvant therapy including gemcitabine.

Methods

Sixty-three patients who underwent neoadjuvant chemoradiation followed by curative surgery for pancreatic ductal adenocarcinomas were included. Immunohistochemistry was performed using resected specimens and the staining intensity of hENT1 was scored as having no staining, low staining, or high staining; the former two were defined as negative expression of hENT1. The association between expression level of hENT1 and overall survival was evaluated by Cox proportional regression model.

Results

Expression level of hENT1 was evaluated as positive in 22 (35%) patients, and as negative in 41 (65%) patients. Univariate analysis showed that regional lymph node metastasis, vascular permeation, and perineural invasion are prognostic factors; however, expression level of hENT1 did not reach statistical significance. Multivariate analysis showed only vascular permeation as a prognostic factor.

Conclusions

Expression level of hENT1 was not associated with prognosis for pancreatic cancer patients who were treated with neoadjuvant chemoradiation including gemcitabine.     

Low MUC4 expression is associated with survival benefit in patients with resectable pancreatic cancer receiving adjuvant gemcitabine

Background: Previous in vitro studies have shown that mucin 4 (MUC4) confers resistance toward gemcitabine in pancreatic cancer cells. To date, there are few clinical studies corroborating these findings. The aim of this study was to evaluate the predictive impact of MUC4 expression on survival in patients with resectable pancreatic cancer receiving adjuvant gemcitabine.

Materials and methods: MUC4 expression was investigated by immunohistochemistry in 78 tissue sections from patients with pancreatic ductal adenocarcinoma undergoing Whipple resection. The H-score was used to evaluate MUC4 expression. The Kaplan–Meier method and Cox proportional hazards regression analysis were used to assess the predictive role of MUC4 expression.

Results: The MUC4 protein was expressed in 93.6% (73/78) of pancreatic cancer tissue specimens. None of the normal control pancreatic tissues had any MUC4 expression. Low MUC4 expression (H-score ≤100) was detectable in 42 (53.8%) of tumors and high MUC4 expression (H-score >100) was detectable in 36 (46.2%) of tumors. Low expression of MUC4 was associated with favorable survival (p?=?.027), whereas high MUC4 expression did not correlate with survival (p?=?.87) in patients receiving adjuvant gemcitabine treatment.

Conclusions: This is the first study indicating a predictive role of MUC4 expression for gemcitabine treatment in the clinical setting.     

Clinical relevance of CD70 expression in resected pancreatic cancer: Prognostic value and therapeutic potential

BackgroundAberrant expression of CD70 in several malignancies is potentially associated with poor patient prognosis and could serve as a therapeutic target. However, the clinical relevance of CD70 expression in pancreatic cancer has not been thoroughly explored.MethodsWe evaluated CD70 expression in 166 surgical specimens obtained from human patients with pancreatic cancer. We analyzed the function of CD70 in proliferation and migration using pancreatic cancer cell lines with silenced CD70 expression.ResultsCD70 expression was positively stained in 42 patients (25%). In the whole cohort, high CD70 expression was not associated with overall survival (OS: 33.1 vs. 40.8 months, P = 0.256), although it was significantly associated with inferior OS in a population of patients that completed adjuvant chemotherapy (OS: 45.4 vs. 63.8 months, P = 0.027). Moreover, the incidence of hematogenous metastasis was significantly higher in patients with high CD70 expression than in those with low CD70 expression (P = 0.020). This finding was also statistically significant in multivariate analyses (P = 0.001). In vitro experiments demonstrated that CD70 expression contributed to cancer cell proliferation independently of gemcitabine treatment as well as cell migration. Furthermore, real-time polymerase chain reaction analysis of frozen surgical tissues showed a correlation between the expression of CD70 and mesenchymal markers.ConclusionsCD70 expression in pancreatic cancer might be involved in hematogenous metastasis. Furthermore, our results imply that CD70 overexpression can serve as a novel prognostic factor and a potential therapeutic target in patients who have completed adjuvant chemotherapy.     

Targeting X-linked inhibitor of apoptosis protein inhibits pancreatic cancer cell growth through p-Akt depletion

AIM: To determine whether lentivirus-mediated shRNA targeting the X-linked inhibitor of apoptosis protein (XIAP) gene could be exploited in the treatment of pancreatic cancer.METHODS: Human pancreatic cancer cells Panc-1, Mia-paca2, Bxpc-3 and SW1990, infected with lentivirus, were analyzed by real-time polymerase chain reaction (PCR). Western blotting was used to examine XIAP protein levels, survivin and p-Akt to confirm the result of real-time PCR and determine the possible mechanism. The 3-(4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to measure IC₅₀ to determine chemosensitivity to the chemotherapeutic drugs 5-fluorouracil (5-FU) and gemcitabine. A colony assay, MTT assay and a tumorigenicity experiment were used to study cell proliferation in vitro and in vivo. Caspase-3/7 activity, 4'',6-diamidino-2-phenylindole-staining and flow cytometric measurements were used to study apoptosis in SW1990 cells.RESULTS: XIAP proteins were found to be differentially expressed among pancreatic cancer cell lines Panc-1, Mia-paca2, Bxpc-3 and SW1990. Data of real-time PCR and Western blotting showed that XIAP was reduced persistently and markedly by lentivirus-mediated shRNA. Downregulation of XIAP by transfection with XIAP shRNA resulted in decreased p-Akt expression. XIAP shRNA also inhibited the growth of pancreatic cancer cells in vitro and in vivo, enhanced drug-induced apoptosis and increased chemosensitivity to 5-FU and gemcitabine. Results also suggest that inhibition of XIAP and subsequent p-Akt depletion may have an anti-tumor effect through attenuating the ability of cancer cells to survive.CONCLUSION: Lentivirus-mediated gene therapy is an attractive strategy in the treatment of pancreatic cancer and justifies the use of lentivirus in pancreatic cancer gene therapy studies.     

Palliative pancreatectomy with postoperative gemcitabine for patients with advanced pancreatic cancer

Background The prognosis of patients with advanced pancreatic cancer remains very poor. This study was designed to evaluate palliative pancreatic resection with postoperative gemcitabine chemotherapy. Methods A total of 127 patients underwent palliative pancreatectomy or palliative nonresectable treatment with gemcitabine at Kobe University Hospital and were analyzed. Results The median survival of patients receiving palliative pancreatectomy with gemcitabine was 15 months, and the 1- and 3-year survival rates were 60% and 13%, respectively, while that of patients receiving gemcitabine alone was only 8 months, and their 1- and 3-year survival rates were 26% and 0%. Multivariate analysis showed that gemcitabine was the strongest factor in survival, and no distant metastasis and pancreatectomy were also significant factors. In addition, the median survival of patients undergoing microscopically incomplete resection with gemcitabine was 22 months, and the 1- and 3-year survival rates were 60% and 40%. Pancreatectomy with gemcitabine improved the performance status 3 months after surgery, with longer survival compared with the gemcitabine alone group. Conclusions Microscopically incomplete pancreatectomy with postoperative gemcitabine chemotherapy has a possible role in advanced pancreatic cancer.     

Impact of gemcitabine on the treatment of metastatic pancreatic cancer

BACKGROUND AND AIM: A previous randomized trial showed gemcitabine was superior to 5-fluorouracil in overall patient survival. However, the incremental improvement in survival was minimal. It is 2.5 years since gemcitabine has become available for the treatment of pancreatic cancer in clinical practice in Japan. The current study was conducted to examine whether treatment outcomes have changed since the introduction of gemcitabine therapy. METHODS: Ninety-one consecutive patients with metastatic pancreatic cancer treated with systemic chemotherapy at the National Cancer Center Hospital East were surveyed. Patients admitted before April 2001 received 5-fluorouracil, and those admitted subsequently received gemcitabine. The patients were divided into the gemcitabine group (n = 50) and the non-gemcitabine group (n = 41), and these groups were compared for five outcomes, objective response rate, non-progressive disease rate, carbohydrate antigen (CA)19-9 response rate, actual survival time, and difference between estimated and observed survivals. The estimated survival time was determined using the prognostic index reported in the previous study. RESULTS: Except for the objective response rate, the four other outcomes in the gemcitabine group were significantly superior to those in the non-gemcitabine group. The frequency of non-progressive disease, CA19-9 response, and favorable prognosis compared with the estimated survival, were 58%, 22%, and 60%, respectively, in the gemcitabine group, and 22%, 6%, 30%, respectively, in the non-gemcitabine group. The median survival time in the gemcitabine and non-gemcitabine group was 5.73 and 2.87 months, respectively. CONCLUSION: It is suggested that there was a definite improvement in pancreatic cancer treatment after gemcitabine was introduced.     

Silencing of LRRFIP1 enhances the sensitivity of gemcitabine in pancreatic cancer cells by activating JNK/c-Jun signaling

BackgroundThe epithelial-mesenchymal transition (EMT) in cancer cells has been shown to closely associate with the survival and drug resistance of cancer cells. We recently provided evidence that Wnt signal activator leucine-rich repeat in flightless-1-interacting protein 1 (LRRFIP1) regulates EMT in pancreatic cancer. LRRFIP1 silencing inhibits the translocation of β-catenin to the nucleus, which led to reverse EMT in cancer cells. It was suggested that LRRFIP1 was implicated in gemcitabine sensitivity by regulating EMT signaling.MethodsGemcitabine chemosensitivity was investigated in LRRFIP1-knockdown pancreatic cancer cells (PANC-1 and MIA Paca-2). In addition, the effects of LRRFIP1 knockdown on JNK/SAPK (stress activated-protein kinase) signaling and apoptosis were evaluated.ResultsLRRFIP1 silencing accelerates gemcitabine-induced caspase activity and cell death in pancreatic cancer cells. It was also revealed that gemcitabine-induced phosphorylation of c-Jun N-terminal kinase (JNK) and c-Jun were increased in LRRFIP1 knockdown cells. The activation of JNK/c-Jun in LRRFIP1-knockdown cells was significantly diminished by the inhibition of Rac activity. It was confirmed that the acquisition of gemcitabine sensitivity by LRRFIP1 silencing largely depends on the stimulation of JNK/SAPK (stress activated-protein kinase) signaling.ConclusionsOur findings suggest that reversing EMT and transient activation of JNK might be essential for the gemcitabine sensitivity in LRRFIP1 knockdown pancreatic cancer cells. Our discoveries highlight the potential role of LRRFIP1 in the chemosensitivity related to the regulation of EMT signaling.     

Chemoradiotherapy with twice-weekly administration of low-dose gemcitabine for locally advanced pancreatic cancer

AIM：To evaluate the chemoradiotherapy for locally advanced pancreatic cancer utilizing low dose gemcitabine as a radiation sensitizer administered twice weekly. METHODS： We performed a retrospective analysis of chemoradiotherapy utilizing gemcitabine administered twice weekly at a dose of 40 mg/m2. After that, maintenance systemic chemotherapy with gemcitabine, at a dose of 1000 mg/m2, was administered weekly for 3 wk with 1-wk rest until disease progression or unacceptable toxicity developed. RESULTS： Eighteen patients with locally advanced unresectable pancreatic cancer were enrolled. Three of those patients could not continue with the therapy; one patient had interstitial pneumonia during radiation therapy and two other patients showed liver metastasis or peritoneal metastasis during an early stage of the therapy. The median survival was 15.0 mo and the overall 1-year survival rate was 60%, while the median progression-free survival was 8.0 mo. The subgroup which showed the reduction of tumor development, more than 50% showed a tendency for a better prognosis; however, other parameters including age, gender and performance status did not correlate with survival. The median survival of the groups that died of liver metastasis and peritoneal metastasis were 13.0 mo and 27.7 mo, respectively.CONCLUSION： Chemoradiotherapy with low-dose gemcitabine administered twice weekly could be effective to patients with locally advanced pancreatic cancer; however, patients developing liver metastases had a worse prognosis. Another chemoradiotherapy strategy might be needed for those patients, such as administrating one or two cycles of chemotherapy initially, followed by chemoradiotherapy for the cases with no distant metastases.     

血管紧张素转化酶Ⅱ对吉西他滨治疗胰腺癌细胞株敏感性的影响

目的探讨血管紧张素转化酶Ⅱ（ACE2）在胰腺癌细胞化学治疗中的作用。方法构建质粒,通过脂质体转染技术将质粒DNA转入胰腺癌细胞株SW1990并建立稳定高表达ACE2的胰腺癌细胞克隆。设实验组（转染ACE2表达质粒）、阴性对照组（转染GFP对照质粒）及未转染组,Western印迹法检测转染后各组细胞ACE2蛋白的表达。采用化学治疗药物吉西他滨作用不同处理组细胞,应用MTT法检测细胞增殖变化,流式细胞仪和TUNEL法检测细胞的凋亡变化。结果50μmol／L吉西他滨干预细胞24h后,实验组、阴性对照组和未转染组的细胞增殖抑制率分别为（51．2±4．8）％、（24．2±3．3）％和（21．3±2．6）％,3组间差异有统计学意义（P〈0．05）;流式细胞计数检测实验组细胞凋亡较阴性对照组及未转染组明显增加[（31．2±3．8）％、（17．64±2．3）％、（15．9±1．7）％,P〈0．05],TUNEL标记分析发现典型凋亡特征。结论稳定高表达ACE2基因可明显增强SW1990对吉西他滨的治疗敏感性,两者联合应用在胰腺癌治疗中具有潜在的价值。     

New developments in the treatment of pancreatic cancer. Highlights from the "44th ASCO Annual Meeting". Chicago, IL, USA. May 30 - June 3, 2008

Pancreatic cancer remains a major therapeutic challenge in 2008. The annual incidence rate of pancreatic cancer is almost identical to the mortality rate; approximately 37,000 new cases are diagnosed each year in the United States, and approximately 33,000 patients die from this disease. Poor prognosis has been attributed to an inability to diagnose pancreatic cancer at an early stage. Majority of patients have advanced pancreatic cancer at the time of diagnosis. Advanced disease is associated with a dismal outcome, with a median survival of 3-6 months. The author summarizes the key studies presented at the 44th ASCO Annual Meeting, Chicago, IL, USA, May 30 - June 3, 2008. CONKO-001 study: final results of the randomized, prospective, multicenter phase III trial of adjuvant chemotherapy with gemcitabine vs. observation in patients with resected pancreatic cancer. E4201 study: a randomized phase III study of gemcitabine in combination with radiation therapy vs. gemcitabine alone in patients with localized, unresectable pancreatic cancer. AViTA study: a randomized, double-blind, placebo-controlled, multicenter phase III trial to evaluate the efficacy and safety of adding bevacizumab to erlotinib and gemcitabine in patients with metastatic pancreatic cancer. CONKO-003 study: final results of a randomized trial in patients with gemcitabine-refractory pancreatic cancer.