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Context: Low-grade appendiceal mucinous neoplasm (LAMN) and appendiceal adenocarcinoma are known to cause the majority of pseudomyxoma peritonei (PMP, i.e. mucinous ascites); however, recognition and proper classification of these neoplasms can be difficult despite established diagnostic criteria., Objective: To determine the pathological diagnostic concordance for appendix neoplasia and related lesions during patient referral to an academic medical center specialized in treating patients with PMP., Design: The anatomic pathology laboratory information system was searched to identify cases over a two-year period containing appendix specimens with mucinous neoplasia evaluated by an outside pathology group and by in-house slide review at a single large academic medical center during patient referral., Results: 161 cases containing appendix specimens were identified over this period. Forty-six of 161 cases (28.6%) contained appendiceal primary neoplasia or lesions. Of these, the originating pathologist diagnosed 23 cases (50%) as adenocarcinoma and 23 cases (50%) as LAMN; however, the reference pathologist diagnosed 29 cases (63.0%) as LAMN, 13 cases (28.3%) as adenocarcinoma, and 4 cases (8.7%) as ruptured simple mucocele. Importantly, for cases in which the originating pathologist rendered a diagnosis of adenocarcinoma, the reference pathologist rendered a diagnosis of adenocarcinoma (56.5%, 13 of 23), LAMN (39.1%, 9 of 23), or simple mucocele (4.3%, 1 of 23). The overall diagnostic concordance rate for these major classifications was 71.7% (33 of 46) with an unweighted observed kappa value of 0.48 (95% CI, 0.27-0.69), consistent with moderate interobserver agreement. All of the observed discordance (28.3%) for major classifications could be attributed to over-interpretation. In addition, the majority of LAMN cases (65.5%) had potential diagnostic deficiencies including over-interpretation as adenocarcinoma and lacking or discordant risk stratification (i.e. documentation of extra-appendiceal neoplastic epithelium)., Conclusions: Appendiceal mucinous lesions remain a difficult area for appropriate pathological classification with substantial discordance due to over-interpretation in this study. The findings highlight the critical need for recognition and application of diagnostic criteria regarding these tumors. Recently published consensus guidelines and a checklist provided herein may help facilitate improvement of diagnostic concordance and thereby reduce over-interpretation and potential overtreatment. Further studies are needed to determine the extent of this phenomenon and its potential clinical impact.

Peritoneal carcinomatosis results from dissemination of solid tumors in the peritoneal cavity, and is a common site of metastasis in patients with carcinomas of gastrointestinal or gynecological origin. Peritoneal carcinomatosis treatment is challenging as poorly vascularized, disseminated peritoneal micro-tumors are shielded from systemic anticancer drugs and drive tumor regrowth. Here, we describe the identification and validation of a tumor homing peptide CKRDLSRRC (IP3), which upon intraperitoneal administration delivers payloads to peritoneal metastases. IP3 peptide was identified by in vivo phage display on a mouse model of peritoneal carcinomatosis of gastric origin (MKN-45P), using high-throughput sequencing of the peptide-encoding region of phage genome as a readout. The IP3 peptide contains a hyaluronan-binding motif, and fluorescein-labeled IP3 peptide bound to immobilized hyaluronan in vitro. After intraperitoneal administration in mice bearing peritoneal metastases of gastric and colon origin, IP3 peptide homed robustly to macrophage-rich regions in peritoneal tumors, including poorly vascularized micro-tumors. Finally, we show that IP3 functionalization conferred silver nanoparticles the ability to home to peritoneal tumors of gastric and colonic origin, suggesting that it could facilitate targeted delivery of nanoscale payloads to peritoneal tumors. Collectively, our study suggests that the IP3 peptide has potential applications for targeting drugs, nanoparticles, and imaging agents to peritoneal tumors.

Importance: KRAS mutations are common in pancreatic cancer, but directly targeting the KRAS protein has thus far been unsuccessful. The aim of this trial was to block the MEK and PI3K/AKT pathways downstream of the KRAS protein as an alternate treatment strategy to slow cancer growth and prolong survival. This was the first cooperative group trial to evaluate this strategy using molecularly targeted oral combination therapy for the treatment of chemotherapy-refractory pancreatic cancer., Objective: To compare selumetinib and MK-2206 vs modified FOLFOX (mFOLFOX) in patients with metastatic pancreatic cancer for whom gemcitabine-based therapy had failed., Design, Setting, and Participants: SWOG S1115 was a randomized phase 2 clinical trial. Between September 2012 and May 2014, 137 patients with metastatic pancreatic adenocarcinoma for whom gemcitabine-based chemotherapy had failed were randomized to selumetinib plus MK-2206 or mFOLFOX. Patients were randomized in a 1:1 fashion and stratified according to duration of prior systemic therapy and presence of liver metastases., Interventions: Patients received selumetinib 100 mg orally per day plus MK-2206 135 mg orally once per week or mFOLFOX (oxaliplatin, 85 mg/m2 intravenous, and fluorouracil, 2400 mg/m2 intravenous infusion over 46-48 hours) on days 1 and 15 of a 28-day cycle., Main Outcomes and Measures: The primary end point of the study was overall survival. Secondary objectives included evaluating toxic effects, objective tumor response, and progression-free survival., Results: There were 58 patients in the selumetinib plus MK-2206 (experimental) arm (60% male; median [range] age, 69 [54-88] years) and 62 patients in the mFOLFOX arm (35% male; median [range] age, 65 [34-82] years). In the experimental arm, median overall survival was shorter (3.9 vs 6.7 months; HR, 1.37; 95% CI, 0.90-2.08; P = .15), as was median progression-free survival (1.9 vs 2.0 months; HR, 1.61; 95% CI, 1.07-2.43; P = .02). One vs 5 patients had a partial response and 12 vs 14 patients had stable disease in the experimental arm vs mFOLFOX arm. Grade 3 or higher toxic effects were observed in 39 patients treated with selumetinib and MK-2206 vs 23 patients treated with mFOLFOX. More patients in the experimental arm discontinued therapy due to adverse events (13 vs 7 patients)., Conclusions and Relevance: Dual targeting of the MEK and PI3K/AKT pathways downstream of KRAS by selumetinib plus MK-2206 did not improve overall survival in patients with metastatic pancreatic adenocarcinoma for whom gemcitabine-based chemotherapy had failed. This was the first randomized prospective evaluation of mFOLFOX in the US population that showed comparable results to CONKO-003 and PANCREOX., Trial Registration: clinicaltrials.gov Identifier: NCT01658943.

Importance: Although consensus statements support the preoperative treatment of borderline resectable pancreatic cancer, no prospective, quality-controlled, multicenter studies of this strategy have been conducted. Existing studies are retrospective and confounded by heterogeneity in patients studied, therapeutic algorithms used, and outcomes reported., Objective: To determine the feasibility of conducting studies of multimodality therapy for borderline resectable pancreatic cancer in the cooperative group setting., Design, Setting, and Participants: A prospective, multicenter, single-arm trial of a multimodality treatment regimen administered within a study framework using centralized quality control with the cooperation of 14 member institutions of the National Clinical Trials Network. Twenty-nine patients with biopsy-confirmed pancreatic cancer preregistered, and 23 patients with tumors who met centrally reviewed radiographic criteria registered. Twenty-two patients initiated therapy (median age, 64 years [range, 50-76 years]; 55% female). Patients registered between May 29, 2013, and February 7, 2014., Interventions: Patients received modified FOLFIRINOX treatment (85 mg/m2 of oxaliplatin, 180 mg/m2 of irinotecan hydrochloride, 400 mg/m2 of leucovorin calcium, and then 2400 mg/m2 of 5-fluorouracil for 4 cycles) followed by 5.5 weeks of external-beam radiation (50.4 Gy delivered in 28 daily fractions) with capecitabine (825 mg/m2 orally twice daily) prior to pancreatectomy., Main Outcomes and Measures: Feasibility, defined by the accrual rate, the safety of the preoperative regimen, and the pancreatectomy rate., Results: The accrual rate of 2.6 patients per month was superior to the anticipated rate. Although 14 of the 22 patients (64% [95% CI, 41%-83%]) had grade 3 or higher adverse events, 15 of the 22 patients (68% [95% CI, 49%-88%]) underwent pancreatectomy. Of these 15 patients, 12 (80%) required vascular resection, 14 (93%) had microscopically negative margins, 5 (33%) had specimens that had less than 5% residual cancer cells, and 2 (13%) had specimens that had pathologic complete responses. The median overall survival of all patients was 21.7 months (95% CI, 15.7 to not reached) from registration., Conclusions and Relevance: The successful completion of this collaborative study demonstrates the feasibility of conducting quality-controlled trials for this disease stage in the multi-institutional setting. The data generated by this study and the logistical elements that facilitated the trial's completion are currently being used to develop cooperative group trials with the goal of improving outcomes for this subset of patients., Trial Registration: clinicaltrials.gov Identifier: NCT01821612., Competing Interests: Disclosures: None reported.

Unlabelled: Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with a low 5-year survival rate, yet new immunotherapeutic modalities may offer hope for this and other intractable cancers. Here, we report that inhibitory targeting of PI3Kγ, a key macrophage lipid kinase, stimulates antitumor immune responses, leading to improved survival and responsiveness to standard-of-care chemotherapy in animal models of PDAC. PI3Kγ selectively drives immunosuppressive transcriptional programming in macrophages that inhibits adaptive immune responses and promotes tumor cell invasion and desmoplasia in PDAC. Blockade of PI3Kγ in PDAC-bearing mice reprograms tumor-associated macrophages to stimulate CD8(+) T-cell-mediated tumor suppression and to inhibit tumor cell invasion, metastasis, and desmoplasia. These data indicate the central role that macrophage PI3Kγ plays in PDAC progression and demonstrate that pharmacologic inhibition of PI3Kγ represents a new therapeutic modality for this devastating tumor type., Significance: We report here that PI3Kγ regulates macrophage transcriptional programming, leading to T-cell suppression, desmoplasia, and metastasis in pancreas adenocarcinoma. Genetic or pharmacologic inhibition of PI3Kγ restores antitumor immune responses and improves responsiveness to standard-of-care chemotherapy. PI3Kγ represents a new therapeutic immune target for pancreas cancer. Cancer Discov; 6(8); 870-85. ©2016 AACR.This article is highlighted in the In This Issue feature, p. 803., Competing Interests: Conflicts: None, (2016 American Association for Cancer Research.)

The RON tyrosine kinase receptor is under investigation as a novel target in pancreatic cancer. While RON mutations are uncommon, RON isoforms are produced in cancer cells via a variety of mechanisms. In this study we sought to: 1) characterize RON isoform expression in pancreatic cancer, 2) investigate mechanisms that regulate isoform expression, and 3) determine how various isoforms effect gene expression, oncogenic phenotypes and responses to RON directed therapies. We quantified RON transcripts in human pancreatic cancer and found expression levels 2500 fold that of normal pancreas with RON isoform expression comprising nearly 50% of total transcript. RNA seq studies revealed that the short form (sfRON) and P5P6 isoforms which have ligand independent activity, induce markedly different patterns of gene expression than wild type RON. We found that transcription of RON isoforms is regulated by promoter hypermethylation as the DNA demethylating agent 5-aza-2'-deoxycytidine decreased all RON transcripts in a subset of pancreatic cancer cell lines. The viability of sfRON-expressing HPDE cells was reduced by a RON specific small molecule inhibitor, while a therapeutic monoclonal antibody had no demonstrable effects. In summary, RON isoforms may comprise half of total RON transcript in human pancreatic cancer and their expression is regulated at least in part by promoter hypermethylation. RON isoforms activate distinct patterns of gene expression, have transforming activity and differential responses to RON directed therapies. These findings further our understanding of RON biology in pancreatic cancer and have implications for therapeutic strategies to target RON activity., Competing Interests: CSF, CE, OS and JE are inventors on a patent application for inhibitors of the RON kinase (PCT/EP2014/001231). CSF and JE are employees of the Lead Discovery Center which is developing RON inhibitors. The other authors have no conflicts of interest to disclose.

Tumor penetrating peptides contain a cryptic (R/K)XX(R/K) CendR element that must be C-terminally exposed to trigger neuropilin-1 (NRP-1) binding, cellular internalization and malignant tissue penetration. The specific proteases that are involved in processing of tumor penetrating peptides identified using phage display are not known. Here we design de novo a tumor-penetrating peptide based on consensus cleavage motif of urokinase-type plasminogen activator (uPA). We expressed the peptide, uCendR (RPARSGR↓SAGGSVA, ↓ shows cleavage site), on phage or coated it onto silver nanoparticles and showed that it is cleaved by uPA, and that the cleavage triggers binding to recombinant NRP-1 and to NPR-1-expressing cells. Upon systemic administration to mice bearing uPA-overexpressing breast tumors, FAM-labeled uCendR peptide and uCendR-coated nanoparticles preferentially accumulated in tumor tissue. We also show that uCendR phage internalization into cultured cancer cells and its penetration in explants of murine tumors and clinical tumor explants can be potentiated by combining the uCendR peptide with tumor-homing module, CRGDC. Our work demonstrates the feasibility of designing tumor-penetrating peptides that are activated by a specific tumor protease. As upregulation of protease expression is one of the hallmarks of cancer, and numerous tumor proteases have substrate specificities compatible with proteolytic unmasking of cryptic CendR motifs, the strategy described here may provide a generic approach for designing proteolytically-actuated peptides for tumor-penetrative payload delivery., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Pancreatic intraepithelial neoplasia is a pre-malignant lesion that can progress to pancreatic ductal adenocarcinoma, a highly lethal malignancy marked by its late stage at clinical presentation and profound drug resistance. The genomic alterations that commonly occur in pancreatic cancer include activation of KRAS2 and inactivation of p53 and SMAD4 (refs 2-4). So far, however, it has been challenging to target these pathways therapeutically; thus the search for other key mediators of pancreatic cancer growth remains an important endeavour. Here we show that the stem cell determinant Musashi (Msi) is a critical element of pancreatic cancer progression both in genetic models and in patient-derived xenografts. Specifically, we developed Msi reporter mice that allowed image-based tracking of stem cell signals within cancers, revealing that Msi expression rises as pancreatic intraepithelial neoplasia progresses to adenocarcinoma, and that Msi-expressing cells are key drivers of pancreatic cancer: they preferentially harbour the capacity to propagate adenocarcinoma, are enriched in circulating tumour cells, and are markedly drug resistant. This population could be effectively targeted by deletion of either Msi1 or Msi2, which led to a striking defect in the progression of pancreatic intraepithelial neoplasia to adenocarcinoma and an improvement in overall survival. Msi inhibition also blocked the growth of primary patient-derived tumours, suggesting that this signal is required for human disease. To define the translational potential of this work we developed antisense oligonucleotides against Msi; these showed reliable tumour penetration, uptake and target inhibition, and effectively blocked pancreatic cancer growth. Collectively, these studies highlight Msi reporters as a unique tool to identify therapy resistance, and define Msi signalling as a central regulator of pancreatic cancer.

Background: Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) has an emerging role in the treatment of peritoneal malignancies. The CRS-HIPEC approach has known treatment-related toxicities. This study sought to determine the predictors of major postoperative complications after CRS-HIPEC in a high-volume center., Methods: From a single-institution database, this study investigated complications experienced by patients undergoing CRS-HIPEC. Multiple preoperative and operative factors were analyzed for their ability to predict 60-day Clavien grade 3 and greater (major) complications by logistic regression. A predictive model was created from preoperative factors using multivariate logistic regression. The model was tested by Akaike's information criterion, the Hosmer and Lemeshow Goodness-of-Fit Test, the receiver operating characteristic, and the Youden Index., Results: The study evaluated 247 patients undergoing CRS-HIPEC. The primary tumor site was the appendix in 166 cases (67.2 %), the colorectal area in 51 cases (20.6 %), the peritoneum (mesothelioma) in 22 cases (8.9 %), the ovary in 5 cases (2 %), and the small bowel in 3 cases (1.2 %). The median peritoneal cancer index was 14 (range 0-29), and 235 patients (95.1 %) had a complete (CC-0/1) cytoreduction. Major complications occurred for 41 patients (16.6 %), classified as grade 3 in 33 cases (13.4 %), grade 4 in 5 cases (2 %), and grade 5 (deaths) in 3 cases (1.2 %). The factors predictive of major complications in the multivariate analysis were a Charlson Comorbidity Index (CCI) score higher than 0 [odds ratio (OR), 2.505; p = 0.035], presence of preoperative symptoms (OR 1.951; p = 0.064), and prior resection status [no resection or prior CRS-HIPEC (OR 2.087) vs. prior resection without CRS-HIPEC (OR 3.209); p = 0.046]. These variables were used to create a tool predictive of postoperative complications., Conclusion: Presence of symptoms, CCI, and prior resection status predict major complications and define a low-risk population after CRS-HIPEC.

Background: Completeness of cytoreduction is a significant predictor of long-term outcome after cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Imaging has limited sensitivity to identify peritoneal metastases and therefore predict whether complete cytoreduction is possible. We reviewed our experience using laparoscopy to determine candidates for complete cytoreduction and HIPEC., Methods: This single-center, retrospective study examined patients from 2007 to 2014 who underwent laparoscopy to determine complete cytoreduction (CC-0/1)/HIPEC candidacy. Preoperative, intraoperative, and postoperative data were collected., Results: A total of 145 laparoscopies were performed on 141 patients, 72 (51.1 %) of whom were female, with a median age of 53 years (range 20-79). The primary site was appendiceal in 67 (47.5 %) patients, colorectal in 43 (30.5 %), mesothelioma in 17 (12.1 %), unknown in 9 (6.4 %), small bowel in 3 (2.1 %), gastric in 1, and ovarian in 1 (0.7 % each). Overall, 115 (81.6 %) patients had prior abdominal surgery, 111 (76.6 %) had evidence of disease on imaging, and 117 (80.7 %) underwent prior chemotherapy, with a median of 5.9 weeks between the last treatment and laparoscopy (0.9-498.9 weeks). Four (2.8 %) intraoperative complications were observed (one liver laceration, two enterotomies, and one air embolus), and nine (6.2 %) postoperative complications [four (2.8 %) Clavien grade (CG) I, three (2.8 %) CG II, one (0.7 %) CG III (return to operating room) and one (0.7 %) CG IV (transient ischemic attack)]. Forty-eight patients deemed candidates by laparoscopy underwent CRS/HIPEC (positive predictive value 82.8 %)., Conclusion: Diagnostic laparoscopy is a safe, feasible, and accurate staging tool in patients with suspected peritoneal metastases being considered for CRS.

Background: Pancreatic ductal adenocarcinoma remains one of the most lethal of all solid tumours. Treatment options are limited and gemcitabine-based chemotherapy remains the standard of care. Although growing evidence shows that p21-activated kinase 1 (PAK1) plays a crucial role in pancreatic cancer, its role has not been fully elucidated. This study aimed to characterise the expression and functional relevance of PAK1 in pancreatic cancer., Methods: PAK1 expression was measured in pancreatic cancer specimens by immunohistochemistry and in pancreatic cancer cell lines by western blotting. The effect of inhibition of PAK1 by either shRNA knock-down (KD), or by a selective inhibitor, FRAX597, alone or in combination with gemcitabine, on cell proliferation and migration/invasion was measured by thymidine uptake and Boyden chamber assays, respectively. The effect on tumour growth and survival was assessed in orthotopic murine models., Results: PAK1 was expressed in all human pancreatic cancer samples tested, an7d was upregulated in all pancreatic cancer cell lines tested. PAK1 KD inhibited pancreatic cancer cell growth and survival, and increased sensitivity to gemcitabine treatment. AKT activity and HIF1α expression were also inhibited. FRAX597 inhibited pancreatic cancer cell proliferation, survival, and migration/invasion. When combined with gemcitabine, FRAX597 synergistically inhibited pancreatic cancer proliferation in vitro and inhibited tumour growth in vivo., Conclusions: These results implicate PAK1 as a regulator of pancreatic cancer cell growth and survival. Combination of a PAK1 inhibitor such as FRAX597 with cytotoxic chemotherapy deserves further study as a novel therapeutic approach to pancreatic cancer treatment.

Peritoneal carcinomatosis is a major source of morbidity and mortality in patients with advanced abdominal neoplasms. Intraperitoneal chemotherapy (IPC) is an area of intense interest given its efficacy in ovarian cancer. However, IPC suffers from poor drug penetration into peritoneal tumors. As such, extensive cytoreductive surgery is required prior to IPC. Here, we explore the utility of iRGD, a tumor-penetrating peptide, for improved tumor-specific penetration of intraperitoneal compounds and enhanced IPC in mice. Intraperitoneally administered iRGD significantly enhanced penetration of an attached fluorescein into disseminated peritoneal tumor nodules. The penetration was tumor-specific, circulation-independent, and mediated by the neuropilin-binding RXXK tissue-penetration peptide motif of iRGD. Q-iRGD, which fluoresces upon cleavage, including the one that leads to RXXK activation, specifically labeled peritoneal metastases displaying different growth patterns in mice. Importantly, iRGD enhanced intratumoral entry of intraperitoneally co-injected dextran to approximately 300% and doxorubicin to 250%. Intraperitoneal iRGD/doxorubicin combination therapy inhibited the growth of bulky peritoneal tumors and reduced systemic drug toxicity. iRGD delivered attached fluorescein and co-applied nanoparticles deep into fresh human peritoneal metastasis explants. These results indicate that intraperitoneal iRGD co-administration serves as a simple and effective strategy to facilitate tumor detection and improve the therapeutic index of IPC for peritoneal carcinomatosis., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Purpose: The role of postoperative therapy in extrahepatic cholangiocarcinoma (EHCC) or gallbladder carcinoma (GBCA) is unknown. S0809 was designed to estimate 2-year survival (overall and after R0 or R1 resection), pattern of relapse, and toxicity in patients treated with this adjuvant regimen., Patients and Methods: Eligibility criteria included diagnosis of EHCC or GBCA after radical resection, stage pT2-4 or N+ or positive resection margins, M0, and performance status 0 to 1. Patients received four cycles of gemcitabine (1,000 mg/m(2) intravenously on days 1 and 8) and capecitabine (1,500 mg/m(2) per day on days 1 to 14) every 21 days followed by concurrent capecitabine (1,330 mg/m(2) per day) and radiotherapy (45 Gy to regional lymphatics; 54 to 59.4 Gy to tumor bed). With 80 evaluable patients, results would be promising if 2-year survival 95% CI were > 45% and R0 and R1 survival estimates were ≥ 65% and 45%, respectively., Results: A total of 79 eligible patients (R0, n = 54; R1, n = 25; EHCC, 68%; GBCA, 32%) were treated (86% completed). For all patients, 2-year survival was 65% (95% CI, 53% to 74%); it was 67% and 60% in R0 and R1 patients, respectively. Median overall survival was 35 months (R0, 34 months; R1, 35 months). Local, distant, and combined relapse occurred in 14, 24, and nine patients. Grade 3 and 4 adverse effects were observed in 52% and 11% of patients, respectively. The most common grade 3 to 4 adverse effects were neutropenia (44%), hand-foot syndrome (11%), diarrhea (8%), lymphopenia (8%), and leukopenia (6%). There was one death resulting from GI hemorrhage., Conclusion: This combination was well tolerated, has promising efficacy, and provides clinicians with a well-supported regimen. Our trial establishes the feasibility of conducting national adjuvant trials in EHCC and GBCA and provides baseline data for planning future phase III trials., (© 2014 by American Society of Clinical Oncology.)

The poors outcomes associated with pancreatic cancer clearly reflect the advanced stage of disease at diagnosis for most patients. Through this lens, it is easy to lose sight of the fact that roughly 50% of patients with pancreatic cancer have no clinically detectable metastases at presentation. Herein, we discuss how patients with localized pancreatic cancer are currently managed. The primary goal of care for patients with resectable and borderline-resectable tumors is cure, facilitated by achieving margin-negative resection of the primary disease and delivering effective adjuvant and/or neoadjuvant therapy. For patients with locally advanced disease, the focus is on limiting local progression and outgrowth of metastatic disease and maintaining quality of life. Although it was once a centerpiece of therapy for localized pancreatic cancer, the value and place of radiation therapy in the treatment algorithm is now under increased scrutiny. In contrast, given its value as demonstrated in multiple prospective trials, chemotherapy is an established part of the treatment paradigm for all patients. With the demonstration that cytotoxic combinations such as fluorouracil, leucovorin, irinotecan, and oxaliplatin as well as gemcitabine/nab-paclitaxel are active in the metastatic setting, these agents are now being studied in patients with localized disease. The neoadjuvant setting provides a particularly favorable setting for evaluating new systemic strategies. Given the array of new targets, including immunomodulatory approaches, there is reason for optimism that we can markedly improve survival for all patients with pancreatic cancer and enter an era in which surgery with curative intent actually fulfills this goal on a much more regular basis., (© 2015 by American Society of Clinical Oncology.)

Background: Long-term survival of patients with appendiceal or colorectal peritoneal carcinomatosis (PC) may be achieved by combining cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS/HIPEC). Unfortunately, such favorable outcomes are realized in a minority of patients. Given the morbidity of the CRS/HIPEC and the uncertain role of postresection systemic therapy, it is important that prognostic factors in high-grade PC be clearly defined., Methods: This single center, retrospective, cohort study examined the outcomes of CRS/HIPEC performed on patients with high-grade PC secondary to appendiceal or colorectal adenocarcinoma between 2007 and 2013. Cox regression analysis was utilized to evaluate the association between potential prognostic factors [age, sex, primary site, lymph node (LN) status, peritoneal cancer index (PCI) score, completeness of cytoreduction score (CC score), number of visceral resections, and systemic chemotherapy] and progression-free survival (PFS)., Results: A total of 70 patients with high-grade appendiceal or colorectal PC underwent CRS/HIPEC during the study period; 82.9 % underwent complete (CC-0) cytoreduction with a median PFS of 9.7 months. Positive LNs at the time of CRS/HIPEC were predictors of worse PFS on univariate and multivariate analysis. No association was demonstrated between pre- or post-HIPEC systemic chemotherapy and PFS., Conclusions: High-grade PC secondary to appendiceal or colorectal adenocarcinoma can be managed with CRS/HIPEC. The number of LN metastases at the time of CRS/HIPEC is the strongest predictor of progression and must be considered when determining patient eligibility for this aggressive treatment.

Introduction: Accumulation of mucinous ascites causes significant morbidity for patients with unresectable pseudomyxoma peritonei (PMP). The success of paracentesis for mucin evacuation is limited due to the presence of adhesions, disease burden, and the viscous nature of mucinous ascites. We sought to review our experience with laparoscopic evacuation of mucinous ascites for palliation of PMP., Methods: Records were reviewed for patients who underwent laparoscopy for carcinomatosis secondary to appendix or colon cancer from July 2007 to January 2014. Of 123 patients, 10 were identified who underwent 17 laparoscopic procedures for palliative evacuation of mucinous ascites., Results: All patients had primary appendiceal cancers and all presented with symptomatic ascites causing abdominal distension and bloating. Pneumoperitoneum was established with a Veress needle or 5-mm optical viewing trocar in the majority of cases (n = 11). In the remaining six cases, an open technique was used and a 10-mm Hasson trocar was placed. There were no trocar-related complications. The median volume of mucin evacuated was 2.0 liters (range 1.7-8.0). All procedures were done as same-day surgeries; no patients required hospitalization. All patients reported symptomatic improvement following the procedure. One patient experienced a grade 1 complication of persistent drainage from one incision, which was managed in the outpatient setting. The median follow-up for all pts was 9.1 months. The median time to recurrent symptoms requiring repeat intervention was 5.3 months., Conclusions: Laparoscopic evacuation of mucinous ascites for select patients with PMP is feasible and results in significant, durable symptom control with minimal morbidity.

Background: Malignant mesothelioma (MM) arises from mesothelial cells that line the pleural, peritoneal and pericardial surfaces. The majority of MMs are pleural and have been associated with asbestos exposure. Previously, pleural MMs have been genetically characterized by the loss of BAP1 (40-60%) as well as loss of NF2 (75%) and CDKN2A (60%). The rare peritoneal form of MM occurs in ~10% cases. With only ~300 cases diagnosed in the US per year, its link to asbestos exposure is not clear and its mutational landscape unknown., Methods: We analyzed the somatic mutational landscape of 12 peritoneal MM of epitheloid subtype using copy number analysis (N = 9), whole exome sequencing (N = 7) and targeted sequencing (N = 12)., Results: Peritoneal MM display few copy number alterations, with most samples having less than 10 Mbp total changes, mostly through deletions and no high copy number amplification. Chromosome band 3p21 encoding BAP1 is the most recurrently deleted region (5/9), while, in contrast to pleural MM, NF2 and CDKN2A are not affected. We further identified 87 non-silent mutations across 7 sequenced tumors, with a median of 8 mutated genes per tumor, resulting in a very low mutation rate (median 1.3 10(-6)). BAP1 was the only recurrently mutated gene (N = 3/7). In one additional case, loss of the entire chromosome 3 leaves a non-functional copy of BAP1 carrying a rare nonsense germline variant, thus suggesting a potential genetic predisposition in this patient. Finally, with targeted sequencing of BAP1 in 3 additional cases, we conclude that BAP1 is frequently altered through copy number losses (N = 3/12), mutations (N = 3/12) or both (N = 2/12) sometimes at a sub-clonal level., Conclusion: Our findings suggest a major role for BAP1 in peritoneal MM susceptibility and oncogenesis and indicate important molecular differences to pleural MM as well as potential strategies for therapy and prevention.

Intrinsic tumor resistance to radiotherapy limits the efficacy of ionizing radiation (IR). Sensitizing cancer cells specifically to IR would improve tumor control and decrease normal tissue toxicity. The development of tumor-targeting technologies allows for developing potent radiosensitizing drugs. We hypothesized that the anti-tubulin agent monomethyl auristatin E (MMAE), a component of a clinically approved antibody-directed conjugate, could function as a potent radiosensitizer and be selectively delivered to tumors using an activatable cell-penetrating peptide targeting matrix metalloproteinases and RGD-binding integrins (ACPP-cRGD-MMAE). We evaluated the ability of MMAE to radiosensitize both established cancer cells and a low-passage cultured human pancreatic tumor cell line using clonogenic and DNA damage assays. MMAE sensitized colorectal and pancreatic cancer cells to IR in a schedule- and dose-dependent manner, correlating with mitotic arrest. Radiosensitization was evidenced by decreased clonogenic survival and increased DNA double-strand breaks in irradiated cells treated with MMAE. MMAE in combination with IR resulted in increased DNA damage signaling and activation of CHK1. To test a therapeutic strategy of MMAE and IR, PANC-1 or HCT-116 murine tumor xenografts were treated with nontargeted free MMAE or tumor-targeted MMAE (ACPP-cRGD-MMAE). While free MMAE in combination with IR resulted in tumor growth delay, tumor-targeted ACPP-cRGD-MMAE with IR produced a more robust and significantly prolonged tumor regression in xenograft models. Our studies identify MMAE as a potent radiosensitizer. Importantly, MMAE radiosensitization can be localized to tumors by targeted activatable cell-penetrating peptides., (©2015 American Association for Cancer Research.)

Single-incision laparoscopic surgery (SILS) is gaining popularity for a wide variety of surgical operations and capitalizes on the benefits of traditional laparoscopic surgery without incurring multiple incision sites. Traditionally, SILS is performed by a midline periumbilical approach. However, such a minimally invasive approach may be utilized in patients who already have an abdominal incision. Our series retrospectively reviews 7 cases in which we utilized the fascial defect at the time of after ostomy reversal as our SILS incision site. In turn, we performed a variety of concurrent intra-abdominal procedures with excellent technical success and outcomes. Our study is the largest single-institution case series of this novel approach and suggests that utilizing an existing ostomy-site abdominal incision is a safe and effective location for SILS port placement and should be considered in patients undergoing concurrent procedures.

Tumor-specific tissue-penetrating peptides deliver drugs into extravascular tumor tissue by increasing tumor vascular permeability through interaction with neuropilin (NRP). Here, we report that a prototypic tumor-penetrating peptide iRGD (amino acid sequence: CRGDKGPDC) potently inhibits spontaneous metastasis in mice. The antimetastatic effect was mediated by the NRP-binding RXXK peptide motif (CendR motif), and not by the integrin-binding RGD motif. iRGD inhibited migration of tumor cells and caused chemorepulsion in vitro in a CendR- and NRP-1-dependent manner. The peptide induced dramatic collapse of cellular processes and partial cell detachment, resulting in the repellent activity. These effects were prominently displayed when the cells were seeded on fibronectin, suggesting a role of CendR in functional regulation of integrins. The antimetastatic activity of iRGD may provide a significant additional benefit when this peptide is used for drug delivery to tumors., (©2014 American Association for Cancer Research.)

Background: Currently, patients with locally advanced esophageal cancer receive neoadjuvant chemoradiotherapy but only about half of these patients benefit from this treatment. GNAS T393C has been shown to predict the postoperative course in solid tumors and may therefore be useful for treatment stratification. The aim of the present study was to determine if the single-nucleotide polymorphism GNAS T393C can be used for treatment stratification in esophageal cancer patients., Methods: A total of 596 patients underwent surgical resection for esophageal carcinoma from 1996 to 2008; 279 patients received chemoradiotherapy prior to surgery (RTX-SURG group). All patients and a reference group of 820 healthy White individuals were genotyped for GNAS T393C., Results: The 5-year-survival rate for the 317 patients who underwent esophagectomy as initial treatment (SURG group) was 57 % for homozygous C-allele carriers (n = 99) and 43 % for T-allele carriers (n = 218; log- rank test p = 0.025). Multivariate analysis revealed the GNAS T393C genotype (p = 0.034), pT (p < 0.001), pN (p < 0.001) and age (p < 0.001) as prognostic of survival. Homozygous C-allele carriers with a locally advanced tumor stage (cT3/T4, n = 129) in the SURG group had a 5-year survival rate of 37 %, which, remarkably, exceeded the 5-year survival rate of 30 % for the entire RTX-SURG group (n = 279). In the RTX-SURG group, the GNAS T393C genotype did not show any prognostic significance., Conclusions: Patients with a locally advanced esophageal cancer and an homozygous GNAS 393C genotype do not benefit from platinum-based neoadjuvant chemoradiotherapy, indicating that these patients should be treated by alternative treatment strategies.

Background: Extensive clinical experience suggests that hyperthermic intraperitoneal chemotherapy (HIPEC) may play an important role in the management of colorectal cancer patients with peritoneal carcinomatosis (CRCPC). However, there remains no established nonsurgical process to rationally select patients for this management, either for inclusion/stratification in clinical trials or as a component of standard of care. The Peritoneal Surface Disease Severity Score (PSDSS) was introduced as a basis to improve patient selection., Methods: The American Society of Peritoneal Surface Malignancies conducted a retrospective review of 1,013 CRCPC patients. The PSDSS was evaluated on 3 specific criteria obtained before surgery (symptoms, extent of peritoneal dissemination, and primary tumor histology). Overall survival was analyzed according to four tiers of disease severity, and a comparison was made between patients who underwent cytoreductive surgery + HIPEC and those who did not., Results: The PSDSS was calculated on 884 patients (87 %). The median survival of 275 patients not undergoing CRS/HIPEC based on their PSDSS-I (n = 8), II (n = 80), III (n = 55), and IV (n = 132)-was 45, 19, 8, and 6 months, respectively. The median survival of 609 patients who underwent CRS/HIPEC based on their PSDSS-I (n = 75), II (n = 317), III (n = 82), and IV (n = 135)-was 86, 43, 29, and 28 months, respectively., Conclusions: These data support that the PSDSS, undertaken before surgery, is capable of defining CRCPC populations who have a statistically defined high or considerably lower likelihood of long-term survival after CRS/HIPEC. The PSDSS can be quite useful in the decision to enter CRCPC patients into, and their stratification within, clinical trials.

Background: Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) are gaining acceptance as treatment for selected patients with colorectal cancer with peritoneal carcinomatosis (CRCPC). Tremendous variations exist in the HIPEC delivery., Methods: The American Society of Peritoneal Surface Malignancies (ASPSM) examined the overall survival in patients with CRCPC who underwent a complete cytoreduction and HIPEC with Oxaliplatin vs. Mitomycin C (MMC), stratifying them by the Peritoneal Surface Disease Severity Score (PSDSS)., Results: Median overall survival (OS) of 539 patients with complete cytoreduction was 32.6 months, 32.7 months for the MMC group and 31.4 months for the Oxaliplatin group (P = 0.925). However, when stratified by PSDSS, median OS rates in PSDSS I/II patients were 54.3 months in those receiving MMC vs. 28.2 months in those receiving oxaliplatin (P = 0.012), whereas in PSDSS III/IV patients, median OS rates were 19.4 months in those receiving MMC vs. 30.4 months in those receiving Oxaliplatin (P = 0.427)., Conclusion: These data suggest that MMC might be a better agent for HIPEC delivery than Oxaliplatin in patients with CRCPC, favorable histologies and low burden of disease (PSDSS I/II) undergoing complete cytoreduction. Prospective studies are warranted, which stratify patients by their PSDSS and randomize them to HIPEC with MMC vs. Oxaliplatin., (© 2014 Wiley Periodicals, Inc.)

Deregulation of protein synthesis is a hallmark of cancer cell proliferation, survival, and metastatic progression. eIF5A1 and its highly related isoform eIF5A2 are translation initiation factors that have been implicated in a range of human malignancies, but how they control cancer development and disease progression is still poorly understood. Here, we investigated how eIF5A proteins regulate pancreatic ductal adenocarcinoma (PDAC) pathogenesis. eIF5A proteins are the only known proteins regulated by a distinct posttranslational modification termed hypusination, which is catalyzed by two enzymes, deoxyhypusine synthase (DHPS) and deoxyhypusine hydroxylase (DOHH). The highly selective nature of the hypusine modification and its amenability to pharmacologic inhibition make eIF5A proteins attractive therapeutic targets. We found that the expression and hypusination of eIF5A proteins are upregulated in human PDAC tissues and in premalignant pancreatic intraepithelial neoplasia tissues isolated from Pdx-1-Cre: LSL-KRAS(G12D) mice. Knockdown of eIF5A proteins in PDAC cells inhibited their growth in vitro and orthotopic tumor growth in vivo, whereas amplification of eIF5A proteins increased PDAC cell growth and tumor formation in mice. Small-molecule inhibitors of DHPS and DOHH both suppressed eIF5A hypusination, preventing PDAC cell growth. Interestingly, we found that eIF5A proteins regulate PDAC cell growth by modulating the expression of PEAK1, a nonreceptor tyrosine kinase essential for PDAC cell growth and therapy resistance. Our findings suggest that eIF5A proteins utilize PEAK1 as a downstream effector to drive PDAC pathogenesis and that pharmacologic inhibition of the eIF5A-hypusine-PEAK1 axis may provide a novel therapeutic strategy to combat this deadly disease., (©2014 American Association for Cancer Research.)

Genetically engineered mouse models (GEMMs) have dramatically improved our understanding of tumor evolution and therapeutic resistance. However, sequential genetic manipulation of gene expression and targeting of the host is almost impossible using conventional Cre-loxP-based models. We have developed an inducible dual-recombinase system by combining flippase-FRT (Flp-FRT) and Cre-loxP recombination technologies to improve GEMMs of pancreatic cancer. This enables investigation of multistep carcinogenesis, genetic manipulation of tumor subpopulations (such as cancer stem cells), selective targeting of the tumor microenvironment and genetic validation of therapeutic targets in autochthonous tumors on a genome-wide scale. As a proof of concept, we performed tumor cell-autonomous and nonautonomous targeting, recapitulated hallmarks of human multistep carcinogenesis, validated genetic therapy by 3-phosphoinositide-dependent protein kinase inactivation as well as cancer cell depletion and show that mast cells in the tumor microenvironment, which had been thought to be key oncogenic players, are dispensable for tumor formation.

Background: Targeting a single pathway in pancreatic adenocarcinoma (PC) is unlikely to affect its natural history. We tested the hypothesis that simulataneous targeting of the epidermal growth factor receptor (EGFR) and insulin-like growth factor receptor-1 (IGF-1R) pathways would significantly improve progression-free survival (PFS) by abrogating reciprocal signaling that promote drug resistance, Methods: This was a phase Ib/II study testing cixutumumab, combined with erlotinib and gemcitabine (G) in patients with untreated metastatic PC. The control arm was erlotinib plus G. The primary end point was PFS. Eligibility included performance status 0/1 and normal fasting blood glucose. Polymorphisms in genes involved in G metabolism and in the EGFR pathway were also studied, Results: The phase I results (n = 10) established the safety of cixutumumab 6 mg/kg/week intravenously, erlotinib 100 mg/day orally, and G 1000 mg/m(2) intravenously on days 1, 8, and 15 of a 28-day cycle. In the RP2 portion (116 eligible patients; median age, 63), the median PFS and overall survival (OS) were 3.6 and 7.0 months, respectively, on the cixutumumab arm, and 3.6 and 6.7 months, respecively, on the control arm. Major grades 3 and 4 toxicities with cixutumumab and control were elevation of transaminases, 12% and 6%, respectively; fatigue, 16% and 12%, respectively; gastrointestinal, 35% and 28%, respectively; neutropenia, 21% and 10%, respectively; and thrombocytopenia, 16% and 7%, respecively. Grade 3/4 hyperglycemia was seen in 16% of patients on cixutumumab. Grade 3 or 4 skin toxicity was similar in both arms of the study (< 5%). No significant differences in PFS by genotype were seen for any of the polymorphisms., Conclusions: Adding the IGF-1R inhibitor cixutumumab to erlotinib and G did not lead to longer PFS or OS in metastatic PC., (© 2014 American Cancer Society.)

Objective: Total pancreatectomy and islet cell autotransplantation (TPIAT) has been increasingly utilized for the management of chronic pancreatitis (CP) with early success. However, the long-term durability of this operation remains unclear., Methods: All patients undergoing TPIAT for the treatment of CP with 5-year or greater follow-up were identified for inclusion in this single-center observational study. End points included narcotic requirements, glycemic control, islet function, quality of life (QOL), and survival., Results: Between 2000 and 2013, 166 patients underwent TPIAT; 112 of these patients had 5-year follow-up data to analyze. All patients underwent successful IAT with a mean of 6027 ± 595 islet equivalents per body weight. There was no perioperative mortality and actuarial survival at 5 years was 94.6%. The narcotic independence rate at 1 year was 55% and continued to improve to 73% at 5-year follow-up (P < 0.05). The insulin independence rate declined over time (38% at 1 year vs 27% at more than 5 years), but insulin requirements remained similar (21.4 vs 24.3 units per day, P = 0.6). All patients achieved stable glycemic control with a median hemoglobin A1C (HgA1C) of 6.9% (range: 5.85%-8.3%). The short form 36-item QOL assessment of a subset of patients available for contact demonstrated continued improvements in all tested modules in patients with at least 5-year follow-up. Two patients developed diabetic complications requiring whole organ pancreas transplant for salvage., Conclusions: This represents one of the largest series examining long-term outcomes after TPIAT. This operation produces durable pain relief and improvement in QOL parameters. Insulin independence rates decline over time, but most patients maintain stable glycemic control.

Pancreatic cancer is the fourth leading cause of cancer death in the United States. While surgical resection remains the only curative option, more than 80% of patients present with unresectable disease. Unfortunately, even among those who undergo resection, the reported median survival is 15-23 mo, with a 5-year survival of approximately 20%. Disappointingly, over the past several decades, despite improvements in diagnostic imaging, surgical technique and chemotherapeutic options, only modest improvements in survival have been realized. Nevertheless, it remains clear that surgical resection is a prerequisite for achieving long-term survival and cure. There is now emerging consensus that a subgroup of patients, previously considered poor candidates for resection because of the relationship of their primary tumor to surrounding vasculature, may benefit from resection, particularly when preceded by neoadjuvant therapy. This stage of disease, termed borderline resectable pancreatic cancer, has become of increasing interest and is now the focus of a multi-institutional clinical trial. Here we outline the history, progress, current treatment recommendations, and future directions for research in borderline resectable pancreatic cancer.

The NCCN Guidelines for Pancreatic Adenocarcinoma discuss the diagnosis and management of adenocarcinomas of the exocrine pancreas and are intended to assist with clinical decision-making. These NCCN Guidelines Insights summarize major discussion points from the 2014 NCCN Pancreatic Adenocarcinoma Panel meeting. The panel discussion focused mainly on the management of borderline resectable and locally advanced disease. In particular, the panel discussed the definition of borderline resectable disease, role of neoadjuvant therapy in borderline disease, role of chemoradiation in locally advanced disease, and potential role of newer, more active chemotherapy regimens in both settings., (Copyright © 2014 by the National Comprehensive Cancer Network.)

Background: Mucinous neoplasms of the appendix (MNA) are rare tumors which may progress from benign to malignant disease with an aggressive biological behavior. MNA is often diagnosed after metastasis to the peritoneal surfaces resulting in mucinous carcinomatosis peritonei (MCP). Genetic alterations in MNA are poorly characterized due to its low incidence, the hypo-cellularity of MCPs, and a lack of relevant pre-clinical models. As such, application of targeted therapies to this disease is limited to those developed for colorectal cancer and not based on molecular rationale., Methods: We sequenced the whole exomes of 10 MCPs of appendiceal origin to identify genome-wide somatic mutations and copy number aberrations and validated significant findings in 19 additional cases., Results: Our study demonstrates that MNA has a different molecular makeup than colorectal cancer. Most tumors have co-existing oncogenic mutations in KRAS (26/29) and GNAS (20/29) and are characterized by downstream PKA activation. High-grade tumors are GNAS wild-type (5/6), suggesting they do not progress from low-grade tumors. MNAs do share some genetic alterations with colorectal cancer including gain of 1q (5/10), Wnt, and TGFβ pathway alterations. In contrast, mutations in TP53 (1/10) and APC (0/10), common in colorectal cancer, are rare in MNA. Concurrent activation of the KRAS and GNAS mediated signaling pathways appears to be shared with pancreatic intraductal papillary mucinous neoplasm., Conclusions: MNA genome-wide mutational analysis reveals genetic alterations distinct from colorectal cancer, in support of its unique pathophysiology and suggests new targeted therapeutic opportunities.

Tumour cells, with stem-like properties, are highly aggressive and often show drug resistance. Here, we reveal that integrin α(v)β₃ serves as a marker of breast, lung and pancreatic carcinomas with stem-like properties that are highly resistant to receptor tyrosine kinase inhibitors such as erlotinib. This was observed in vitro and in mice bearing patient-derived tumour xenografts or in clinical specimens from lung cancer patients who had progressed on erlotinib. Mechanistically, α(v)β₃, in the unliganded state, recruits KRAS and RalB to the tumour cell plasma membrane, leading to the activation of TBK1 and NF-κB. In fact, α(v)β₃ expression and the resulting KRAS-RalB-NF-κB pathway were both necessary and sufficient for tumour initiation, anchorage independence, self-renewal and erlotinib resistance. Pharmacological targeting of this pathway with bortezomib reversed both tumour stemness and erlotinib resistance. These findings not only identify α(v)β₃ as a marker/driver of carcinoma stemness but also reveal a therapeutic strategy to sensitize such tumours to RTK inhibition.

Importance: Interest in minimally invasive distal pancreatectomy (MIDP) has grown in recent years, but currently available data are limited. Greater insight into application patterns and outcomes may be gained from a national database inquiry., Objectives: To study trends in the use of MIDP and compare the short-term outcomes of MIDP with those of open distal pancreatectomy., Design, Setting, and Participants: Population-based retrospective cohort study evaluating perioperative outcomes and hospital charge measures for distal pancreatectomy, comparing the surgical approaches and adjusting for patient- and hospital-level factors, among patients undergoing elective distal pancreatectomy from 1998 to 2009 in the Nationwide Inpatient Sample in a 20% stratified sample of all US hospitals., Main Outcomes and Measures: In-hospital mortality, rates of perioperative complications and splenectomy, total charges, and length of stay., Results: A total of 8957 distal pancreatectomies were included in this analysis, of which 382 (4.3%) were MIDPs. On a national level, this projected to 42,320 open distal pancreatectomies and 1908 MIDPs. The proportion of distal pancreatectomies performed via minimally invasive approaches tripled between 1998 and 2009, from 2.4% to 7.3%. The groups were comparable for sex and comorbidity profiles, while patients who underwent MIDP were 1.5 years older. On multivariate analysis, MIDP was associated with lower rates of overall predischarge complications, including lower incidences of postoperative infections and bleeding complications, as well as a shorter length of stay by 1.22 days. There were no differences in rates of in-hospital mortality, concomitant splenectomy, or total charges., Conclusions and Relevance: This population-based study of MIDP reveals that the application of this approach has tripled in practice and provides strong evidence that MIDP has evolved into a safe option in the treatment of benign and malignant pancreatic diseases.

Pancreatic cancer remains a devastating disease with a mortality rate that has not changed substantially in decades. Novel therapies are therefore desperately needed. The RON receptor tyrosine kinase has been identified as an important mediator of KRAS oncogene addiction and is overexpressed in the majority of pancreatic cancers. Preclinical studies show that inhibition of RON function decreases pancreatic cancer cell migration, invasion, and survival and can sensitize pancreatic cancer cells to chemotherapy. This article reviews the current state of knowledge regarding RON biology and pancreatic cancer and discusses its potential as a therapeutic target.

Background: Gastrointestinal stromal tumor (GIST) is the most common sarcoma and its treatment with imatinib has served as the paradigm for developing targeted anti-cancer therapies. Despite this success, imatinib-resistance has emerged as a major problem and therefore, the clinical efficacy of other drugs has been investigated. Unfortunately, most clinical trials have failed to identify efficacious drugs despite promising in vitro data and pathological responses in subcutaneous xenografts. We hypothesized that it was feasible to develop orthotopic patient-derived xenografts (PDXs) from resected GIST that could recapitulate the genetic heterogeneity and biology of the human disease., Methods: Fresh tumor tissue from three patients with pathologically confirmed GISTs was obtained immediately following tumor resection. Tumor fragments (4.2-mm3) were surgically xenografted into the liver, gastric wall, renal capsule, and pancreas of immunodeficient mice. Tumor growth was serially assessed with ultrasonography (US) every 3-4 weeks. Tumors were also evaluated with positron emission tomography (PET). Animals were sacrificed when they became moribund or their tumors reached a threshold size of 2500-mm3. Tumors were subsequently passaged, as well as immunohistochemically and histologically analyzed., Results: Herein, we describe the first model for generating orthotopic GIST PDXs. We have successfully xenografted three unique KIT-mutated tumors into a total of 25 mice with an overall success rate of 84% (21/25). We serially followed tumor growth with US to describe the natural history of PDX growth. Successful PDXs resulted in 12 primary xenografts in NOD-scid gamma or NOD-scid mice while subsequent successful passages resulted in 9 tumors. At a median of 7.9 weeks (range 2.9-33.1 weeks), tumor size averaged 473 ± 695-mm³ (median 199-mm3, range 12.6-2682.5-mm³) by US. Furthermore, tumor size on US within 14 days of death correlated with gross tumor size on necropsy. We also demonstrated that these tumors are FDG-avid on PET imaging, while immunohistochemically and histologically the PDXs resembled the primary tumors., Conclusions: We report the first orthotopic model of human GIST using patient-derived tumor tissue. This novel, reproducible in vivo model of human GIST may enhance the study of GIST biology, biomarkers, personalized cancer treatments, and provide a preclinical platform to evaluate new therapeutic agents for GIST.

Objectives: To develop a mouse model for multispectral fluorescence imaging of the pancreas and pancreatic microenvironment., Methods: Cre/loxP technology was used to develop this model. We crossed mT/mG indicator mice, engineered to constitutively express a conditional tdTomato transgene that converts to green fluorescent protein (GFP) expression after exposure to Cre recombinase, with Pdx1-Cre transgenic mice. To characterize this model for studies of pancreas biology, we performed bright light and fluorescence imaging of body cavities and intact organs and confocal microscopy of pancreata from offspring of Pdx1-Cre and mT/mG crosses., Results: Pdx1-Cre-mT/mG mice demonstrated bright GFP expression within the pancreas and duodenum and intense tdTomato expression in all other organs. Green fluorescent protein expression was mosaic in Pdx1-Cre-mT/mG pancreata, with most showing extensive conversion from tdTomato to GFP expression within the epithelial-derived elements of the pancreatic parenchyma. Because both GFP and tdTomato are membrane targeted, individual cell borders were clearly outlined in confocal images of mT/mG pancreata., Conclusions: This mouse model enables multispectral fluorescence imaging of individual cells and cell processes at the microscopic level of the pancreatic microenvironment; it should prove valuable for a variety of fluorescence imaging studies, ranging from pancreatic development to pancreatic cancer biology.

Background: Methodological limitations of prior studies have prevented progress in the treatment of patients with borderline resectable pancreatic adenocarcinoma. Shortcomings have included an absence of staging and treatment standards and pre-existing biases with regard to the use of neoadjuvant therapy and the role of vascular resection at pancreatectomy., Methods: In this manuscript, we review limitations of studies of borderline resectable PDAC reported to date, highlight important controversies related to this disease stage, emphasize the research infrastructure necessary for its future study, and present a recently-approved Intergroup pilot study (Alliance A021101) that will provide a foundation upon which subsequent well-designed clinical trials can be performed., Results: We identified twenty-three studies published since 2001 which report outcomes of patients with tumors labeled as borderline resectable and who were treated with neoadjuvant therapy prior to planned pancreatectomy. These studies were heterogeneous in terms of the populations studied, the metrics used to characterize therapeutic response, and the indications used to select patients for surgery. Mechanisms used to standardize these and other issues that are incorporated into Alliance A021101 are reviewed., Conclusions: Rigorous standards of clinical trial design incorporated into trials of other disease stages must be adopted in all future studies of borderline resectable pancreatic cancer. The Intergroup trial should serve as a paradigm for such investigations.

Despite our improved understanding of pancreatic cancer biology and ability to perform more complex pancreatic cancer surgeries that produce better short-term outcomes, major progress toward increasing survival times has been painstakingly slow. Through the often-repeated, dismal survival statistics, it is easy to lose sight of real progress that has been made in pancreatic cancer therapy. It is particularly interesting to observe the extent to which these advances are interdependent and the effects they have had on practice. For example, during the past 5-10 years, we have seen widespread adoption of pancreatic imaging protocols that allow for objectively defined criteria of resectability. This has led to the definition of "borderline resectable pancreatic cancer"--a new clinical category that has affected the design of clinical trials. A major change in our surgical approach has been the move to minimally invasive pancreatectomy, which continues to gain broader acceptance and use, particularly for left-sided lesions. Although many new agents have been developed aimed at putative molecular targets, recent breakthroughs in therapy for advanced disease have arisen from our ability to safely give patients combination cytotoxic chemotherapy. We are now faced with the challenge of combining multidrug, cytotoxic chemotherapies with newer-generation agents. Ultimately, the hope is that drug combinations will be selected based on biomarkers, and strategies for pancreatic cancer therapy will be personalized, which could prolong patients' lives and reduce toxicity. We review the major advances in pancreatic cancer therapy during the last 5 years, and discuss how these have set the stage for greater progress in the near future., (Copyright © 2013 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Lymph nodes are initial sites of tumor metastasis, yet whether the lymph node microenvironment actively promotes tumor metastasis remains unknown. We show here that VEGF-C/PI3Kα-driven remodeling of lymph nodes promotes tumor metastasis by activating integrin α4β1 on lymph node lymphatic endothelium. Activated integrin α4β1 promotes expansion of the lymphatic endothelium in lymph nodes and serves as an adhesive ligand that captures vascular cell adhesion molecule 1 (VCAM-1)(+) metastatic tumor cells, thereby promoting lymph node metastasis. Experimental induction of α4β1 expression in lymph nodes is sufficient to promote tumor cell adhesion to lymphatic endothelium and lymph node metastasis in vivo, whereas genetic or pharmacological blockade of integrin α4β1 or VCAM-1 inhibits it. As lymph node metastases accurately predict poor disease outcome, and integrin α4β1 is a biomarker of lymphatic endothelium in tumor-draining lymph nodes from animals and patients, these results indicate that targeting integrin α4β1 or VCAM to inhibit the interactions of tumor cells with the lymph node microenvironment may be an effective strategy to suppress tumor metastasis.

Pancreatic ductal adenocarcinoma is the most aggressive of all epithelial malignancies. In contrast to the favorable trends seen in most other common malignancies, the five-year survival of patients with this disease remains only 6%, a statistic that has changed minimally for decades. Only two drugs have been approved by the U.S. Food and Drug Administration (FDA) for use in pancreatic cancer in the last 15 years, and there are no established strategies for early detection.

Objectives: Pancreatic cancer remains one of the deadliest diseases, with limited surgical and treatment options. Two targets of interest include the transcription factor nuclear factor-κB and cyclooxygenase-2, which are constitutively activated and overexpressed, respectively, in human pancreatic adenocarcinoma. We have previously shown that dimethylaminoparthenolide (DMAPT), a bioavailable nuclear factor-κB inhibitor, and the cyclooxygenase inhibitors sulindac and celecoxib have potential chemotherapeutic efficacy. The current study evaluates the efficacy of intervention with DMAPT and sulindac in the LSL-Kras(G12D);Pdx-1-Cre genetically engineered mouse model. Gemcitabine, traditionally a chemotherapeutic agent, has relatively low toxicity; thus, combinations with low-dose gemcitabine were also explored., Methods: LSL-Kras(G12D);Pdx-1-Cre mice at 7 months of age were randomized into placebo, DMAPT (40 mg/kg per day), sulindac (20 mg/kg per day), gemcitabine (50 mg/kg twice weekly), and combination treatment groups. After 3 months of treatment, the mice were killed., Results: The percentage of normal pancreatic ducts was significantly increased by the combinations of DMAPT/sulindac, DMAPT/gemcitabine, sulindac/gemcitabine, and DMAPT/sulindac/gemcitabine compared to placebo. Additionally, the percentage of mouse pancreatic intraepithelial neoplasia-2 lesions was significantly decreased by DMAPT/gemcitabine., Conclusions: Intervention with DMAPT and sulindac in combination with gemcitabine may delay or prevent progression of premalignant pancreatic lesions in the LSL-Kras(G12D);Pdx-1-Cre mouse model of pancreatic cancer.

The recepteur d'origine nantais (RON) receptor tyrosine kinase is overexpressed and stimulates invasive growth in pancreatic cancer cells, yet the mechanisms that underlie RON-mediated phenotypes remain poorly characterized. To better understand RON function in pancreatic cancer cells, we sought to identify novel RON interactants using multidimensional protein identification analysis. These studies revealed plectin, a large protein of the spectrin superfamily, to be a novel RON interactant. Plectin is a multifunctional protein that complexes with integrin-β4 (ITGB4) to form hemidesmosomes, serves as a scaffolding platform crucial to the function of numerous protein signaling pathways and was recently described as an overexpressed protein in pancreatic cancer (Bausch D et al., Clin Cancer Res 2010; Kelly et al., PLoS Med 2008;5:e85). In this study, we demonstrate that on exposure to its ligand, macrophage-stimulating protein, RON binds to plectin and ITGB4, which results in disruption of the plectin-ITGB4 interaction and enhanced cell migration, a phenotype that can be recapitulated by small hairpin ribosomal nucleic acid (shRNA)-mediated suppression of plectin expression. We demonstrate that disruption of plectin-ITGB4 is dependent on RON and phosphoinositide-3 (PI3) kinase, but not mitogen-activated protein kinase (MEK), activity. Thus, in pancreatic cancer cells, plectin and ITGB4 form hemidesmosomes which serve to anchor cells to the extracellular matrix (ECM) and restrain migration. The current study defines a novel interaction between RON and plectin, provides new insight into RON-mediated migration and further supports efforts to target RON kinase activity in pancreatic cancer., (Copyright © 2012 UICC.)

Early biomarkers and effective therapeutic strategies are desperately needed to treat pancreatic ductal adenocarcinoma (PDAC), which has a dismal 5-year patient survival rate. Here, we report that the novel tyrosine kinase PEAK1 is upregulated in human malignancies, including human PDACs and pancreatic intraepithelial neoplasia (PanIN). Oncogenic KRas induced a PEAK1-dependent kinase amplification loop between Src, PEAK1, and ErbB2 to drive PDAC tumor growth and metastasis in vivo. Surprisingly, blockade of ErbB2 expression increased Src-dependent PEAK1 expression, PEAK1-dependent Src activation, and tumor growth in vivo, suggesting a mechanism for the observed resistance of patients with PDACs to therapeutic intervention. Importantly, PEAK1 inactivation sensitized PDAC cells to trastuzumab and gemcitabine therapy. Our findings, therefore, suggest that PEAK1 is a novel biomarker, critical signaling hub, and new therapeutic target in PDACs., (©2012 AACR.)

Background: Previously assumed to be a select ligand for chemokine receptor CXCR4, chemokine CXCL12 is now known to activate both CXCR4 and CXCR7. However, very little is known about the co-expression of these receptors in cancer cells., Methods: We used immunohistochemistry to determine the extent of co-expression in pancreatic cancer tissue samples and immunoblotting to verify expression in pancreatic cancer cell lines. In cell culture studies, siRNA was used to knock down expression of CXCR4, CXCR7, K-Ras and β-arrestin -2 prior to stimulating the cells with CXCL12. Activation of the mitogen-activated protein kinase pathway (MAPK) was assessed using both a Raf-pull down assay and western blotting. The involvement of the receptors in CXCL12-mediated increases in cell proliferation was examined via an ATP-based proliferation assay., Results: First, we discovered frequent CXCR4/CXCR7 co-expression in human pancreatic cancer tissues and cell lines. Next, we observed consistent increases in ERK1/2 phosphorylation after exposure to CXCL12 or CXCL11, a CXCR7 agonist, in pancreatic cancer cell lines co-expressing CXCR4/CXCR7. To better characterize the receptor-mediated pathway(s), we knocked down CXCR4 or CXCR7, exposed the cells to CXCL12 and examined subsequent effects on ERK1/2. We observed that CXCR7 mediates the CXCL12-driven increase in ERK1/2 phosphorylation. Knockdown of CXCR4 expression however, decreased levels of K-Ras activity. Conversely, KRAS knockdown greatly reduced CXCL12-mediated increases in ERK1/2 phosphorylation. We then evaluated the role of β-arrestin-2, a protein directly recruited by chemokine receptors. We observed that β-arrestin-2 knockdown also inhibited increases in ERK1/2 phosphorylation mediated by both CXCR4 and CXCR7. Finally, we investigated the mechanism for CXCL12-enhanced cell proliferation and found that either receptor can modulate cell proliferation., Conclusions: In summary, our data demonstrate that CXCR4 and CXCR7 are frequently co-expressed in human pancreatic cancer tissues and cell lines. We show that β-arrestin-2 and K-Ras dependent pathways coordinate the transduction of CXCL12 signals. Our results suggest that the development of therapies based on inhibiting CXCL12 signaling to halt the growth of pancreatic cancer should be focused at the ligand level in order to account for the contributions of both receptors to this signaling pathway.

Inactivation of tumor suppressor gene p16/INK4A and oncogenic activation of KRAS occur in almost all pancreatic cancers. To better understand the roles of p16 in pancreatic tumorigenesis, we created a conditional p16 knockout mouse line (p16flox/flox), in which p16 is specifically disrupted in a tissue-specific manner without affecting p19/ARF expression. p16flox/flox; LSL-KrasG12D; Pdx1-Cre mice developed the full spectrum of pancreatic intraepithelial neoplasia (mPanIN) lesions, pancreatic ductal adenocarcinoma (PDA), and metastases were observed in all the mice. Here we report a mouse model that simulates human pancreatic tumorigenesis at both genetic and histologic levels and is ideal for studies of metastasis. During the progression from primary tumors to metastases, the wild-type allele of Kras was progressively lost (loss of heterozygosity at Kras or LOH at Kras) in p16flox/flox; LSL- KrasG12D; Pdx1-Cre mice. These observations suggest a role for Kras beyond tumor initiation. In vitro assays performed with cancer cell lines derived from primary pancreatic tumors of these mice showed that cancer cells with LOH at Kras exhibited more aggressive phenotypes than those retained the wild-type Kras allele, indicating that LOH at Kras can provide cancer cells functional growth advantages and promote metastasis. Increased LOH at KRAS was also observed in progression of human pancreatic primary tumors to metastases, again supporting a role for the KRAS gene in cancer metastasis. This finding has potential translational implications- future KRAS target therapies may need to consider targeting oncogenic KRAS specifically without inhibiting wild-type KRAS function.

The RON receptor tyrosine kinase (RTK) is overexpressed in the majority of pancreatic cancers, yet its role in pancreatic cancer cell biology remains to be clarified. Recent work in childhood sarcoma identified RON as a mediator of resistance to insulin-like growth factor receptor (IGF1-R)-directed therapy. To better understand RON function in pancreatic cancer cells, we sought to identify novel RON interactants. Using multidimensional protein identification analysis, IGF-1R was identified and confirmed to interact with RON in pancreatic cancer cell lines. IGF-1 induces rapid phosphorylation of RON, but RON signaling did not activate IGF-1R indicating unidirectional signaling between these RTKs. We next demonstrate that IGF-1 induces pancreatic cancer cell migration that is RON dependent, as inhibition of RON signaling by either shRNA-mediated RON knockdown or by a RON kinase inhibitor abrogated IGF-1 induced wound closure in a scratch assay. In pancreatic cancer cells, unlike childhood sarcoma, STAT-3, rather than RPS6, is activated in response to IGF-1, in a RON-dependent manner. The current study defines a novel interaction between RON and IGF-1R and taken together, these two studies demonstrate that RON is an important mediator of IGF1-R signaling and that this finding is consistent in both human epithelial and mesenchymal cancers. These findings demand additional investigation to determine if IGF-1R independent RON activation is associated with resistance to IGF-1R-directed therapies in vivo and to identify suitable biomarkers of activated RON signaling.

Pancreas cancer is one of the most lethal malignancies and is characterized by activating mutations of Kras, present in 95% of patients. More than 60% of pancreatic cancers also display increased c-Src activity, which is associated with poor prognosis. Although loss of tumor suppressor function (for example, p16, p53, Smad4) combined with oncogenic Kras signaling has been shown to accelerate pancreatic duct carcinogenesis, it is unclear whether elevated Src activity contributes to Kras-dependent tumorigenesis or is simply a biomarker of disease progression. Here, we demonstrate that in the context of oncogenic Kras, activation of c-Src through deletion of C-terminal Src kinase (CSK) results in the development of invasive pancreatic ductal adenocarcinoma (PDA) by 5-8 weeks. In contrast, deletion of CSK alone fails to induce neoplasia, while oncogenic Kras expression yields PDA at low frequency after a latency of 12 months. Analysis of cell lines derived from Ras/Src-induced PDA's indicates that oncogenic Ras/Src cooperativity may lead to genomic instability, yet Ras/Src-driven tumor cells remain dependent on Src signaling and as such, Src inhibition suppresses growth of Ras/Src-driven tumors. These findings demonstrate that oncogenic Ras/Src cooperate to accelerate PDA onset and support further studies of Src-directed therapies in pancreatic cancer.

Purpose: The most common preclinical models of pancreatic adenocarcinoma utilize human cells or tissues that are xenografted into immunodeficient hosts. Several immunocompetent, genetically engineered mouse models of pancreatic cancer exist; however, tumor latency and disease progression in these models are highly variable. We sought to develop an immunocompetent, orthotopic mouse model of pancreatic cancer with rapid and predictable growth kinetics., Experimental Design: Cell lines with epithelial morphology were derived from liver metastases obtained from Kras(G12D/+);LSL-Trp53(R172H/+);Pdx-1-Cre mice. Tumor cells were implanted in the pancreas of immunocompetent, histocompatible B6/129 mice, and the mice were monitored for disease progression. Relevant tissues were harvested for histologic, genomic, and immunophenotypic analysis., Results: All mice developed pancreatic tumors by two weeks. Invasive disease and liver metastases were noted by six to eight weeks. Histologic examination of tumors showed cytokeratin-19-positive adenocarcinoma with regions of desmoplasia. Genomic analysis revealed broad chromosomal changes along with focal gains and losses. Pancreatic tumors were infiltrated with dendritic cells, myeloid-derived suppressor cells, macrophages, and T lymphocytes. Survival was decreased in RAG(-/-) mice, which are deficient in T cells, suggesting that an adaptive immune response alters the course of disease in wild-type mice., Conclusions: We have developed a rapid, predictable orthotopic model of pancreatic adenocarcinoma in immunocompetent mice that mimics human pancreatic cancer with regard to genetic mutations, histologic appearance, and pattern of disease progression. This model highlights both the complexity and relevance of the immune response to invasive pancreatic cancer and may be useful for the preclinical evaluation of new therapeutic agents., (Copyright 2010 AACR.)