The clinical landscape of cell-free DNA alterations in 1671 patients with advanced biliary tract cancer.

BACKGROUND: Targeted therapies have transformed clinical management of advanced biliary tract cancer (BTC). Cell-free DNA (cfDNA) analysis is an attractive approach for cancer genomic profiling that overcomes many limitations of traditional tissue-based analysis. We examined cfDNA as a tool to inform clinical management of patients with advanced BTC and generate novel insights into BTC tumor biology. PATIENTS AND METHODS: We analyzed next-generation sequencing data of 2068 cfDNA samples from 1671 patients with advanced BTC generated with Guardant360. We carried out clinical annotation on a multi-institutional subset (n = 225) to assess intra-patient cfDNA-tumor concordance and the association of cfDNA variant allele fraction (VAF) with clinical outcomes. RESULTS: Genetic alterations were detected in cfDNA in 84% of patients, with targetable alterations detected in 44% of patients. Fibroblast growth factor receptor 2 (FGFR2) fusions, isocitrate dehydrogenase 1 (IDH1) mutations, and BRAF V600E were clonal in the majority of cases, affirming these targetable alterations as early driver events in BTC. Concordance between cfDNA and tissue for mutation detection was high for IDH1 mutations (87%) and BRAF V600E (100%), and low for FGFR2 fusions (18%). cfDNA analysis uncovered novel putative mechanisms of resistance to targeted therapies, including mutation of the cysteine residue (FGFR2 C492F) to which covalent FGFR inhibitors bind. High pre-treatment cfDNA VAF was associated with poor prognosis and shorter response to chemotherapy and targeted therapy. Finally, we report the frequency of promising targets in advanced BTC currently under investigation in other advanced solid tumors, including KRAS G12C (1.0%), KRAS G12D (5.1%), PIK3CA mutations (6.8%), and ERBB2 amplifications (4.9%). CONCLUSIONS: These findings from the largest and most comprehensive study to date of cfDNA from patients with advanced BTC highlight the utility of cfDNA analysis in current management of this disease. Characterization of oncogenic drivers and mechanisms of therapeutic resistance in this study will inform drug development efforts to reduce mortality for patients with BTC.

Real-Time Targeted Genome Profile Analysis of Pancreatic Ductal Adenocarcinomas Identifies Genetic Alterations That Might Be Targeted With Existing Drugs or Used as Biomarkers.

BACKGROUND & AIMS: It has been a challenge to select treatment for patients with pancreatic ductal adenocarcinomas (PDACs) based on genome alterations. We performed targeted genomic profile analyses of a large number of PDACs to assess the full spectrum of actionable genomic alterations. METHODS: We performed targeted genomic profile analyses of 3594 PDAC samples from an international cohort, including capture-based targeted genomic profiling of as many as 315 cancer-associated genes and intron regions of 28 genes that are rearranged in cancer cells. Tumor mutation burden (TMB) and microsatellite instability (MSI) status were also assessed. TMB was calculated across a 1.14-megabase region; TMB-high was defined as ≥20 mutations/megabase. MSI-high status was assigned based on analysis of 114 intron homopolymer loci. RESULTS: KRAS, TP53, CDKN2A, and SMAD4 were the most frequently altered genes in PDAC. We found KRAS mutations in 88% of samples. Among PDACs without mutations in KRAS, we found alterations in genes whose products are in the mitogen-activated protein kinase signaling pathway and are candidate drug targets (actionable targets, n = 132; 4%), as well as gene fusions (n = 51), gene amplifications (n = 35), genes with missense mutations (n = 30), and genes that contain deletions (n = 16). Many of these encode proteins in receptor tyrosine kinase, RAS, or mitogen-activated protein kinase signaling pathways. Aside from TP53, alterations in genes encoding DNA damage repair proteins (BRCA and FANC) were detected in 14% of PDACs. Among PDACs evaluated for MSI (n = 2563) and TMB (n = 1021), MSI-high and/or TMB-high phenotypes were detected in 0.5% of samples. Alterations in FGF23, CCND2, PIK3CA, and FGF6 were more commonly detected in intraductal papillary mucinous neoplasm-associated PDACs. CONCLUSIONS: In targeted genomic profile analyses of 3594 PDACs, we found 17% to contain genomic alterations that might make the tumor cells susceptible to currently used anticancer agents. We identified mutations in genes that could contribute to progression of intraductal papillary mucinous neoplasms into malignancies. These alterations might be used as biomarkers for early detection.

Surfaceome profiling enables isolation of cancer-specific exosomal cargo in liquid biopsies from pancreatic cancer patients.

Background: Detection of circulating tumor DNA can be limited due to their relative scarcity in circulation, particularly while patients are actively undergoing therapy. Exosomes provide a vehicle through which cancer-specific material can be enriched from the compendium of circulating non-neoplastic tissue-derived nucleic acids. We carried out a comprehensive profiling of the pancreatic ductal adenocarcinoma (PDAC) exosomal 'surfaceome' in order to identify surface proteins that will render liquid biopsies amenable to cancer-derived exosome enrichment for downstream molecular profiling. Patients and methods: Surface exosomal proteins were profiled in 13 human PDAC and 2 non-neoplastic cell lines by liquid chromatography-mass spectrometry. A total of 173 prospectively collected blood samples from 103 PDAC patients underwent exosome isolation. Droplet digital PCR was used on 74 patients (136 total exosome samples) to determine baseline KRAS mutation call rates while patients were on therapy. PDAC-specific exosome capture was then carried out on additional 29 patients (37 samples) using an antibody cocktail directed against selected proteins, followed by droplet digital PCR analysis. Exosomal DNA in a PDAC patient resistant to therapy were profiled using a molecular barcoded, targeted sequencing panel to determine the utility of enriched nucleic acid material for comprehensive molecular analysis. Results: Proteomic analysis of the exosome 'surfaceome' revealed multiple PDAC-specific biomarker candidates: CLDN4, EPCAM, CD151, LGALS3BP, HIST2H2BE, and HIST2H2BF. KRAS mutations in total exosomes were detected in 44.1% of patients undergoing active therapy compared with 73.0% following exosome capture using the selected biomarkers. Enrichment of exosomal cargo was amenable to molecular profiling, elucidating a putative mechanism of resistance to PARP inhibitor therapy in a patient harboring a BRCA2 mutation. Conclusion: Exosomes provide unique opportunities in the context of liquid biopsies for enrichment of tumor-specific material in circulation. We present a comprehensive surfaceome characterization of PDAC exosomes which allows for capture and molecular profiling of tumor-derived DNA.

Phase 1b investigation of the MEK inhibitor binimetinib in patients with advanced or metastatic biliary tract cancer.

Background The MAPK pathway plays a central role in regulation of several cellular processes, and its dysregulation is a hallmark of biliary tract cancer (BTC). Binimetinib (MEK162), a potent, selective oral MEK1/2 inhibitor, was assessed in patients with advanced BTC. Patients and Methods An expansion cohort study in patients who received ≤1 line of therapy for advanced BTC was conducted after determination of the maximum tolerated dose in this Phase 1 trial. Patients received binimetinib 60 mg twice daily. The primary objectives were to characterize the safety profile and pharmacokinetics of binimetinib in advanced BTC. Secondary objectives included assessment of clinical efficacy, changes in weight and lean body mass, and pharmacodynamic effects. Tumor samples were assessed for mutations in relevant genes. Results Twenty-eight patients received binimetinib. Common adverse events (AEs) were mild, with rash (82%) and nausea (54%) being most common. Two patients experienced grade 4 AEs, one generalized edema and the other pulmonary embolism. The pharmacokinetics in this patient population were consistent with those previously reported (Bendell JC et al., Br J Cancer 2017;116:575-583). Twelve patients (43%) experienced stable disease and two had objective responses (1 complete response, 1 partial response) per Response Evaluation Criteria in Solid Tumors and stable metabolic disease by positron emission tomography/computed tomography. Most patients (18/25; 72%) did not have KRAS, BRAF, NRAS, PI3KCA, or PTEN mutations, nor was there correlation between mutation status and response. The average non-fluid weight gain was 1.3% for lean muscle and 4.7% for adipose tissue. Conclusion Binimetinib was well tolerated and showed promising evidence of activity in patients with BTC. Correlative studies suggested the potential for binimetinib to promote muscle gain in patients with BTC.

Prognostic value of carbohydrate antigen 19-9 in patients undergoing resection of biliary tract cancer.

BACKGROUND: The clinical significance of abnormally high levels of carbohydrate antigen (CA) 19-9 after resection of biliary tract cancer (BTC) is not well established. The aim of this study was to determine the prognostic value of CA19-9 normalization in patients undergoing resection of BTC with curative intent. METHODS: Patients with BTC undergoing resection with curative intent (1996-2015) were divided into those with normal preoperative CA19-9 level (normal CA19-9 group), those with an abnormally high preoperative CA19-9 level (over 37 units/ml) and normal postoperative CA19-9 level (normalization group), and those with an abnormally high preoperative CA19-9 level and abnormally high postoperative CA19-9 level (non-normalization group). Overall survival (OS) was analysed and predictors of OS were determined. RESULTS: The normal CA19-9 group (180 patients) and normalization group (74) had better OS than the non-normalization group (58) (3-year OS rate 70·4, 73 and 31 per cent respectively; both P < 0·001). The normal CA19-9 and normalization groups had equivalent OS (P = 0·880). On multivariable analysis, factors associated with worse OS were lymph node metastases (hazard ratio (HR) 1·78; P = 0·014) and abnormally high postoperative CA19-9 level (HR 3·16; P < 0·001). In the normalization group, OS did not differ after R0 versus R1 resection (3-year OS rate 69 versus 62 per cent respectively; P = 0·372); in the non-normalization group, patients with R1 resection had worse OS (3-year OS rate 36 and 20 per cent for R0 and R1 respectively; P = 0·032). CONCLUSION: Non-normalization of CA19-9 level after resection of BTC with curative intent was associated with worse OS. R1 resection was associated with a particularly poor prognosis when CA19-9 levels did not normalize.

Novel therapeutic strategy targeting the Hedgehog signalling and mTOR pathways in biliary tract cancer.

BACKGROUND: Activation of the PI3K/mTOR and Hedgehog (Hh) signalling pathways occurs frequently in biliary tract cancer (BTC). Crosstalk between these pathways occurs in other gastrointestinal cancers. The respective signalling inhibitors rapamycin and vismodegib may inhibit BTC synergistically and suppress cancer stem cells (CSCs). METHODS: Gene expression profiling for p70S6k and Gli1 was performed with BTC cell lines. Tumour and pathway inhibitory effects of rapamycin and vismodegib were investigated in BTC preclinical models and CSCs. RESULTS: Rapamycin and vismodegib synergistically reduced BTC cell viability and proliferation. This drug combination arrested BTC Mz-ChA-1 cells in the G1 phase but had no significant effect on the cell cycle of BTC Sk-ChA-1 cells. Combined treatment inhibited the proliferation of CSCs and ALDH-positive cells. Nanog and Oct-4 expression in CSCs was decreased by the combination treatment. Western blotting results showed the p-p70S6K, p-Gli1, p-mTOR, and p-AKT protein expression were inhibited by the combination treatment in BTC cells. In an Mz-ChA-1 xenograft model, combination treatment resulted in 80% inhibition of tumour growth and prolonged tumour doubling time. In 4 of 10 human BTC specimens, tumour p-p70S6K and Gli1 protein expression levels were decreased with the combination treatment. CONCLUSIONS: Targeted inhibition of the PI3K/mTOR and Hhpathways indicates a new avenue for BTC treatment with combination therapy.

Varlitinib plus capecitabine in second-line advanced biliary tract cancer: a randomized, phase II study (TreeTopp).

BACKGROUND: Patients with advanced biliary tract cancer who progress on first-line therapy have limited treatment options. The TreeTopp study assessed varlitinib, a reversible small molecule pan-human epidermal growth factor receptor inhibitor, plus capecitabine in previously treated advanced biliary tract cancer. PATIENTS AND METHODS: This global, double-blind, randomized, placebo-controlled phase II study enrolled patients with confirmed unresectable or metastatic biliary tract cancer and disease progression after one prior line of gemcitabine-containing chemotherapy. Patients received oral varlitinib 300 mg or placebo twice daily (b.i.d.) for 21 days, plus oral capecitabine 1000 mg/m2 b.i.d. on days 1-14, in 21-day treatment cycles. Co-primary endpoints were objective response rate and progression-free survival (PFS) according to RECIST v1.1 by Independent Central Review. RESULTS: In total, 127 patients received varlitinib plus capecitabine (n = 64) or placebo plus capecitabine (n = 63). The objective response rate was 9.4% with varlitinib plus capecitabine versus 4.8% with capecitabine alone (odds ratio 2.28; P = 0.42). Median PFS was 2.83 versus 2.79 months [hazard ratio (HR), 0.90; 95% confidence interval (CI), 0.60-1.37; P = 0.63] and overall survival was 7.8 versus 7.5 months (HR, 1.11; 95% CI, 0.69-1.79; P = 0.66), respectively. In a subgroup analysis, the addition of varlitinib appeared to provide a PFS benefit in female patients (median, 4.1 versus 2.8 months; HR, 0.59; 95% CI, 0.28-1.23) and those with gallbladder cancer (median, 2.9 versus 1.6 months; HR, 0.55; 95% CI, 0.26-1.19). Grade ≥3 treatment-emergent adverse events were reported in 65.6% of patients receiving varlitinib plus capecitabine versus 58.7% of those receiving capecitabine alone. CONCLUSIONS: In patients with advanced biliary tract cancer, second-line treatment with varlitinib plus capecitabine was well tolerated but did not improve efficacy versus capecitabine alone. A PFS benefit was suggested in female patients and those with gallbladder cancer.

The role of PARP in DNA repair and its therapeutic exploitation.

Historically, PARP inhibitors (PARPi) were developed to potentiate the cytotoxic effect of certain chemotherapeutic agents and are currently being investigated in combination with chemotherapy in diverse cancer types. These agents are also radiosensitisers and clinical trials of PARPi with concurrent radiation are required. It has long been recognised that defective DNA repair pathways lead to tumour susceptibility. Recent studies indicate that tumour cells with defective homologous recombination (HR) repair pathways, the classic example being BRCA mutations, are exquisitely sensitive to PARPi. Defects in HR are not restricted to BRCA-associated tumours and other cancer types may be enriched for HR defects and hence susceptible to PARP inhibition. The identification of predictive markers for sensitivity to PARP inhibition is a priority area for research.

Bevacizumab combined with gemcitabine and capecitabine for advanced pancreatic cancer: a phase II study.

A total of 50 patients with advanced pancreatic cancer were enrolled in a phase II study of bevacizumab 15 mg kg(-1), capecitabine 1300 mg m(-2) daily for 2 weeks and gemcitabine 1000 mg m(-2) weekly 2 times; cycles were repeated every 21 days. Radiological response rate was 22%; progression-free survival and over survival were 5.8 and 9.8 months respectively. Grade 3 or 4 toxicities included neutropaenia (22%), thrombocytopaenia (14%), thromboembolic events (12%), hypertension (8%) and haemorrhage (6%).

Epithelial-mesenchymal transition (EMT) and activated extracellular signal-regulated kinase (p-Erk) in surgically resected pancreatic cancer.

BACKGROUND: EMT or transformation to the mesenchymal phenotype plays an important role in tumor invasion and metastasis. In vitro data suggest that mesenchymal transformation may correlate with the activation of PI3 kinase and Ras/Erk pathways. We investigated the expression of EMT markers (low E-cadherin, high fibronectin, and vimentin) and their association with p-Erk in resected pancreatic cancer. METHODS: Clinical data/surgical specimens from 34 consecutive pancreatic cancer patients (pts) who underwent pancreatectomy were included. Immunohistochemical staining was performed on formalin-fixed paraffin-embedded tissues using monoclonal antibodies against vimentin, fibronectin, E-cadherin, and p-Erk. The results were correlated with clinicopathological parameters and survival. Survival analysis (log-rank test, Cox proportional hazard model), categorical data analysis (Pearson's chi-square, Fisher's exact test) and Kendall's tau were performed at a significance level of 0.05. RESULTS: The patient population was formed from 13 males and 21 females, with a median age of 66 years (range 38-84 years); American Joint Committee on Cancer (AJCC) stage 1 (n = 2), 2 (n = 27), 3 (n = 5); histological grade 1 (n = 4), 2 (n = 13), 3 (n = 16), 4 (n = 1). Median survival was 15 months (95% CI: 11-24 months). Fibronectin overexpression correlated with the presence of vimentin (p = 0.0048) and activated Erk (p = 0.0264). There was a borderline association of fibronectin with worsening grade (p = 0.06). A negative association between vimentin and E-cadherin was noted (p = 0.0024). Increased fibronectin or vimentin and decreased E-cadherin correlated with poor survival. CONCLUSION: EMT is associated with poor survival in surgically resected pancreatic adenocarcinoma. A correlation between activated Erk and fibronectin was identified that may open avenues for targeted therapy for this subgroup.

Epidermal growth factor receptor-directed therapy in esophageal cancer.

Esophageal adenocarcinoma (EAC) is one of the fastest growing malignancies in the US. The long-term survival of patients with this cancer remains poor; only 25% of patients undergoing surgical excision are alive after 5 years. Multimodal programs that incorporate radiotherapy, chemotherapy and surgery for localized tumors may result in a modest survival advantage. However, significant strides in this disease can result from the inclusion of targeted therapies. The epidermal growth factor receptor (EGFR) family represents one such target and is receiving increasing attention due to the advent of specific inhibitors. Studies conducted by us and others have shown that the overexpression of EGFR family signaling intermediates is common in Barrett's esophagus and EAC. In the latter case, EGFR expression may have prognostic significance. EGFR inhibitors, including oral tyrosine kinase inhibitors and monoclonal antibodies, result in a synergistic antitumor effect with chemotherapeutic agents or with radiotherapy. Therefore, several ongoing studies include EGFR-directed therapy either alone or in combination with chemoradiotherapy for this disease. Our study of gefitinib, oxaliplatin and radiotherapy suggested that gefitinib can be safely incorporated into an oxaliplatin-based chemoradiation program for esophageal cancer, although the clinical activity of this combination is modest. Herein, we review the current literature on this subject.

Expression of genes related to activity of oxaliplatin and 5-fluorouracil in endoscopic biopsies of primary esophageal cancer in patients receiving oxaliplatin, 5-flourouracil and radiation: characterization and exploratory analysis with survival.

With a goal of identifying relations between gene expression and response (mucosal or pathological) or survival in esophageal cancer patients (stages II to IV) receiving oxaliplatin, 5-fluorouracil (5FU) and radiation, we measured in endoscopic primary tumor biopsies from 38 patients, the expression of seven genes (gammaGCS, gammaGT, MRP-2, ERCC-1, XPA, TS and DPD) prior to treatment, 1 week following oxaliplatin alone and at the end of the combined radio-chemotherapy cycle using real time QRT-PCR. A higher pretreatment level of XPA was related to shorter survival with a hazard ratio of 2.43 (90% confidence interval 1.09 to 5.43) using Cox regression modeling. However, multivariate analysis with a Cox model indicated low expression of XPA or TS and combined stages II and III had a higher probability of survival (for XPA: hazard ratio 3.0 and 90% C.I. of 1.3 to 6.9, with adjustment for stage included; for TS: hazard ratio is 1.98 with 90% C.I. of 0.94 to 4.20. The expression of TS, gammaGCS, ERCC-1 and MRP-2 declined from D 1 to the end of the cycle (p<0.05, sign test). A validation and further understanding of the findings need to be carried out in a larger study with a more homogeneous population of patients.

Biologic mesh spacer placement facilitates safe delivery of dose-intense radiation therapy: A novel treatment option for unresectable liver tumors.

INTRODUCTION: Patients with unresectable liver tumors who fail initial treatment modalities have a poor prognosis (<1 yr). Although effective, delivery of high dose radiation therapy to these tumors is limited by proximity of radiosensitive bowel. We have previously reported that placement of a biologic mesh spacer (BMS) can effectively displace the bowel allowing for dose-intense radiation to be delivered with low short-term toxicity. The purpose of this study was to assess and report the long-term safety and oncologic outcomes of this cohort. METHODS: From 2012 to 2014 seven patients with unresectable hepatic malignancy (6 IHCC, 1 CRLM) underwent BMS (acellular human dermis) placement (2 open, 5 MIS) prior to radiation therapy. Prospective registry data were reviewed for tumor and treatment details, progression, metastasis and survival. RTOG guidelines were used to define radiation toxicities. RESULTS: Mean patient age was 50.4 years (30-62 years) and 4 patients were male (57.1%). Prior to surgery, all patients had been treated for an average of 12.5 months with surgery, chemotherapy, radiation and/or TACE. After surgery, all patients recovered well and received a mean radiation dose of 76.1 Gy (58.1-100 Gy) over 13-25 fractions. 1 patient received SBRT; 4 fractions, 10 Gy each. Maximum dose delivered was 100 Gy (Biologic Equivalent Dose of 140 Gy, α/ß = 10). Mean time to initiation of radiation therapy was 24 days (12-48 days) from surgery. No significant GI toxicity was recorded, and no GI bleeding or ulcers were observed. Mean follow-up after XRT was 18.2 months (5.5-31 months). Three patients had no loco-regional progression of disease. 2 patients had infield progression of liver disease and another had progressive lymphadenopathy. 3 patients developed pulmonary metastasis, at a mean time to distant failure of 3 months. There are 4 survivors over 2-years from surgery. CONCLUSION: For patients with unresectable liver tumors, placement of a BMS enhances the safety and efficacy of high-dose radiotherapy, providing a survival benefit via delay in time to progression compared to traditional treatments with no significant short or long term GI toxicity.

S-phase modulation by irinotecan: pilot studies in advanced solid tumors.

Two studies of irinotecan (CPT-11) followed 24 h later by an antimetabolite were conducted. The objectives of the studies were: (1) to determine whether the increase in S-phase in tumor cells seen 24 h after CPT-11 administration in animal studies is seen in advanced solid tumors in patients, (2) to determine the dose of CPT-11 required to produce this effect, (3) to compare two methods (immunohistochemistry, IHC, for cyclin A, and DNA flow cytometry, FC) for evaluating S-phase in tumor biopsies from patients, and (4) to establish the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of CPT-11, given 24 h before gemcitabine (GEM, 1000 mg/m(2)). In one study CPT-11 was followed 24 h later by 5-fluorouracil (5-FU), 400 mg/m(2) per week for 4 weeks every 6 weeks. Tumor biopsies were obtained before and 24 h after CPT-11 administration before administration of 5-FU and assayed for S-phase by IHC for cyclin A and by FC. The starting dose of CPT-11 was 80 mg/m(2) per week with subsequent exploration of 40 and 60 mg/m(2) per week to establish the dose-effect relationship of the increase in tumor cells in S-phase. In the second study, CPT-11 was given 24 h before GEM 1000 mg/m(2) per week for 2 weeks every 3 weeks. Doses of 20-80 mg/m(2) were explored to establish the MTD and DLT and to study tumor cell S-phase in selected patients. CPT-11 80 mg/m(2) produced a mean increase in S-phase by IHC for cyclin A of 137%. Lesser increases were seen with 40 and 60 mg/m(2). CPT-11 followed 24 h later by 5-FU 400 mg/m(2) per week for 4 weeks was well tolerated. In the study of CPT-11 followed by GEM 1000 mg/m(2), 60 mg/m(2) of CPT-11 was the MTD.

Evolving strategies of cytotoxic chemotherapy for advanced prostate cancer.

Despite the use of cytotoxic chemotherapy for advanced prostate cancer for half a century, its clinical utility in this setting remains undefined. Based on traditional methods of assessment, the list of the most active cytotoxic agents includes cyclophosphamide, doxorubicin, mitoxantrone and cisplatin. With the introduction of more structured methods of assessment, including careful assessment of indices of quality of life and serial measurement of serum prostate-specific antigen (PSA), the role of cytotoxic agents is being re-assessed. In view of the cell cycle characteristics of prostate cancer, there appears to be an emerging role for combination inhibitors of mitosis, including estramustine in combination with the vinca alkaloids, etoposide or paclitaxel.

Systemic Therapy for Invasive Bladder Cancer.

BACKGROUND: Bladder cancer is one of the most common malignancies in Western society. In the United States, approximately 10,000 of these patients present with invasive disease, and more progress from superficial bladder cancer. METHODS: The authors review the literature on systemic treatment for both localized and metastatic bladder cancer, and they include their experience in defining approaches to various stages of disease. RESULTS: Cisplatin-based combination chemotherapy is the most effective systemic approach for advanced bladder cancers, although few patients are cured. Neoadjuvant, perspective, and adjuvant trials, as well as concurrent chemoradiation studies, are in progress to attempt to demonstrate better outcomes. CONCLUSIONS: The combination of systemic chemotherapy and definitive local therapy may have a useful role in the management of locally advanced bladder cancers, but optimal schedules and true survival benefit have not been established.

Locally advanced pancreatic cancer: the role of definitive chemoradiotherapy.

At the time of diagnosis, around 20% of patients with pancreatic cancer present at a resectable stage, 50% have metastatic disease and 30% have locally advanced tumour, non-metastatic but unresectable because of superior mesenteric artery or coeliac encasement. Despite advances in chemoradiotherapy and improved systemic chemotherapeutic agents, patients with locally advanced pancreatic cancer suffer from high rates of distant metastatic failure and from local progression, with a median survival time ranging from 5 to 11 months. In the past 30 years, modest improvements in median survival have been attained for these patients treated by chemoradiotherapy or chemotherapy protocols. The optimal therapy for patients with locally advanced pancreatic carcinoma remains controversial. This review aims to evaluate the role of radiotherapy for these patients.

Cell death/proliferation roles for nc886, a non-coding RNA, in the protein kinase R pathway in cholangiocarcinoma.

We have recently identified nc886 (pre-miR-886 or vtRNA2-1) as a novel type of non-coding RNA that inhibits activation of protein kinase R (PKR). PKR's pro-apoptotic role through eukaryotic initiation factor 2 α (eIF2α) phosphorylation is well established in the host defense against viral infection. Paradoxically, some cancer patients have elevated PKR activity; however, its cause and consequence are not understood. Initially, we evaluated the expression of nc886, PKR and eIF2α in non-malignant cholangiocyte and cholangiocarcinoma (CCA) cells. nc886 is repressed in CCA cells and this repression is the cause of PKR's activation therein. nc886 alone is necessary and sufficient for suppression of PKR via direct physical interaction. Consistently, artificial suppression of nc886 in cholangiocyte cells activates the canonical PKR/eIF2α cell death pathway, suggesting a potential significance of the nc886 suppression and the consequent PKR activation in eliminating pre-malignant cells during tumorigenesis. In comparison, active PKR in CCA cells does not induce phospho-eIF2α nor apoptosis, but promotes the pro-survival nuclear factor-κB pathway. Thus, PKR has a dual life or death role during tumorigenesis. Similarly to the CCA cell lines, nc886 tends to be decreased but PKR tends to be activated in our clinical samples from CCA patients. Collectively from our data, we propose a tumor surveillance model for nc886's role in the PKR pathway during tumorigenesis.

The potential for poly (ADP-ribose) polymerase inhibitors in cancer therapy.

The modulation of DNA repair pathways for therapeutic benefit in cancer has now become a reality with the development of poly (ADP-ribose) polymerase inhibitors (PARPi). PARP is involved in single-strand DNA breaks, which in the presence of defective homologous recombination repair lead to double-strand DNA breaks, the most lethal form of DNA damage. These agents therefore may be the drugs of choice for BRCA mutant breast and ovarian cancers. PARPi result in synergistic antitumor effects when combined with cisplatin, temozolomide, topoisomerase inhibitors and ionizing radiation. The indications for PARPi lie beyond BRCA mutations and may include genomic and functional defects in DNA repair and damage response pathways. Several PARPi are in the clinical development phase at this time and, given the recent failure of a phase III clinical trial of iniparib in triple-negative breast cancer, the identification of structural and functional differences between these inhibitors becomes critical. Acquired resistance to PARPi is being noted and represents an important limitation in this field. A concise review of the literature in this field is presented.