The Florida Pancreas Collaborative Next-Generation Biobank: Infrastructure to Reduce Disparities and Improve Survival for a Diverse Cohort of Patients with Pancreatic Cancer

Background: Well-annotated, high-quality biorepositories provide a valuable platform to support translational research. However, most biorepositories have poor representation of minority groups, limiting the ability to address health disparities. Methods: We describe the establishment of the Florida Pancreas Collaborative (FPC), the first state-wide prospective cohort study and biorepository designed to address the higher burden of pancreatic cancer (PaCa) in African Americans (AA) compared to Non-Hispanic Whites (NHW) and Hispanic/Latinx (H/L). We provide an overview of stakeholders; study eligibility and design; recruitment strategies; standard operating procedures to collect, process, store, and transfer biospecimens, medical images, and data; our cloud-based data management platform; and progress regarding recruitment and biobanking. Results: The FPC consists of multidisciplinary teams from fifteen Florida medical institutions. From March 2019 through August 2020, 350 patients were assessed for eligibility, 323 met inclusion/exclusion criteria, and 305 (94%) enrolled, including 228 NHW, 30 AA, and 47 H/L, with 94%, 100%, and 94% participation rates, respectively. A high percentage of participants have donated blood (87%), pancreatic tumor tissue (41%), computed tomography scans (76%), and questionnaires (62%). Conclusions: This biorepository addresses a critical gap in PaCa research and has potential to advance translational studies intended to minimize disparities and reduce PaCa-related morbidity and mortality.

Concomitant neuroendocrine tumor and gastrointestinal stromal tumor in a duodenal fine needle aspiration: A cytologic clue for neurofibromatosis type 1

The identification of two cell populations displaying different cytologic characteristics in the same fine needle aspiration (FNA), one with an epithelioid appearance and the other spindle cell morphology, is an extremely rare phenomenon and potentially represents a source of diagnostic confusion. Depending on the lineage and relationship of the two cell types, the differential diagnosis is broad and encompasses a wide spectrum of entities. The current case describes the presence of nests and clusters of neuroendocrine cells associated with rare spindle cell fragments of gastrointestinal stromal tumor (GIST) in the same fine needle aspiration of a duodenal mass. Our literature analysis revealed that such combined cytologic findings were hitherto never reported and the concurrence of well-differentiated neuroendocrine tumor (NET) and GIST is almost pathognomonic for neurofibromatosis type 1 (NF-1).

Identification of a novel IL-5 signaling pathway in chronic pancreatitis and crosstalk with pancreatic tumor cells

BACKGROUND

While inflammation is associated with pancreatic cancer, the underlying mechanisms leading to cancer initiation are still being delineated. Eosinophils may promote or inhibit tumor growth, although the specific role in pancreatic cancer has yet to be determined. Eosinophil-supporting cytokine interleukin-5 and receptor are likely to have a role, but the significance in the pancreatic cancer microenvironment is unknown.

METHODS

Genetically engineered Akt1^Myr/KRas^G12D and KRas^G12D mice were used to model changes induced by chronic inflammation. Tissue samples were collected to analyze the tumor microenvironment and infiltration of immune cells, whereas serum was collected to analyze cytokine and amylase activity in the inflammatory model. The expression of IL-5R and the effects of IL-5 were analyzed in human and murine tumor cells.

RESULTS

Compound Akt1^Myr/KRas^G12D mice, compared to single KRas^G12D or Akt1^Myr mice, exhibited increased tissue damage after repeat inductions of inflammation, and had accelerated tumor development and metastasis. M2 macrophages and newly identified eosinophils co-localized with fibrotic regions rather than infiltrating into tumors, consistent with immune cell privilege. The majority of eosinophils found in the pancreas of Akt1^Myr/KRas^G12D mice with chronic inflammation lacked the cytotoxic NKG2D marker. IL-5 expression was upregulated in pancreatic cells in response to inflammation, and then diminished in advanced lesions. Although not previously described in pancreatic tumors, IL-5Rα was increased during mouse pancreatic tumor progression and expressed in human pancreatic ductal adenocarcinomas (7 of 7 by immunohistochemistry). IL-5 stimulated tumor cell migration and activation through STAT5 signaling, thereby suggesting an unreported tumor-promoting role for IL-5Rα in pancreatic cancer.

CONCLUSIONS

Chronic inflammation induces increased pancreatic cancer progression and immune cells such as eosinophils are attracted to areas of fibrosis. Results suggest that IL-5 in the pancreatic compartment stimulates increased IL-5Rα on ductal tumor cells to increase pancreatic tumor motility. Collectively, IL-5/IL-5Rα signaling in the mouse and human pancreatic tumors microenvironment is a novel mechanism to facilitate tumor progression. Additional file 1: Video Abstract.

K-RAS Mutant Gene Found in Pancreatic Juice Activated Chromatin From Peri-ampullary Adenocarcinomas

External pancreatic duct stents inserted after resection of pancreatic head tumors provide unique access to pancreatic juice analysis of genetic and metabolic components that may be associated with peri-ampullary tumor progression. For this pilot study, portal venous blood and pancreatic juice samples were collected from 17 patients who underwent pancreaticoduodenectomy for peri-ampullary tumors. Portal vein circulating tumor cells (CTC) were isolated by high-speed fluorescence-activated cell sorting (FACS) and analyzed by quantitative reverse transcription polymerase chain reaction (RT-PCR) for K-RAS exon 12 mutant gene expression (K-RASmut). DNA, chromatin, and histone acetylated active chromatin were isolated from pancreatic juice samples by chromatin immunoprecipitation (ChIP) and the presence of K-RASmut and other cancer-related gene sequences detected by quantitative polymerase chain reaction (PCR) and ChIP-Seq. Mutated K-RAS gene was detectable in activated chromatin in pancreatic juice secreted after surgical resection of pancreatic, ampullary and bile duct carcinomas and directly correlated with the number of CTC found in the portal venous blood (P = .0453). ChIP and ChIP-Seq detected acetylated chromatin in peri-ampullary cancer patient juice containing candidate chromatin loci, including RET proto-oncogene, not found in similar analysis of pancreatic juice from non-malignant ampullary adenoma. The presence of active tumor cell chromatin in pancreatic juice after surgical removal of the primary tumor suggests that viable cancer cells either remain or re-emerge from the remnant pancreatic duct, providing a potential source for tumor recurrence and cancer relapse. Therefore, epigenetic analysis for active chromatin in pancreatic juice and portal venous blood CTC may be useful for prognostic risk stratification and potential identification of molecular targets in peri-ampullary cancers.

Pancreatic and bile duct cancer circulating tumor cells (CTC) form immune-resistant multi-cell type clusters in the portal venous circulation

Circulating tumor cells (CTC) enter the blood from many carcinomas and represent a likely source of metastatic dissemination. In contrast to the peripheral circulation, KRAS mutation- positive CTC thrive in the portal venous blood of patients with pancreatic ductal adenocarcinoma (PDAC). To analyze the essential interactions that contribute to carcinoma CTC growth and immune resistance, portal venous blood was collected during pancreatico-duodenectomy in 41 patients with peri-ampullary pathologies (PDAC = 11; ampullary adenocarcinoma (AA) = 15; distal cholangiocarcinoma (CC) = 6; IPMN = 7; non-malignant pancreatitis = 2). FACS-isolated cell populations from the portal circulation were reconstituted ex vivo using mixed cell reaction cultures (MCR). During the first 48hr, PDAC, AA, and CC patient CTC were all highly proliferative (mean 1.7 hr/cell cycle, 61.5% ± 20% growing cells) and resistant to apoptosis (mean 39% ±  25% apoptotic cells). PDAC CTC proliferation and resistance to T cell cytotoxicity were decreased among patients who received pre-operative chemotherapy (p = 0.0019, p = 0.0191, respectively). After 7 days in culture, CTC from PDAC, CC, and AA patients recruited multiple immune cell types, including CD105 + CD14 + myeloid fibroblasts, to organize into spheroid-like clusters. It was only in PDAC and CC-derived MCR that cluster formation promoted CTC survival, growth, and fibroblast differentiation. FACS depletion of CTC or myeloid fibroblast cells eliminated cluster network formation, and re-introduction of these cell populations reconstituted such ability. Our findings suggest that PDAC and CC CTC survival within the portal venous circulation is supported by their interactions with immune cells within multi-cell type clusters that could represent vectors of local recurrence and metastatic progression.

Abstract 2916: Targeting lysophospholipid metabolism inhibits pancreatic cancer cell proliferation under nutrient-limiting conditions

Patients with pancreatic ductal adenocarcinoma (PDAC) have a poor prognosis, and more effective systemic treatments for patients with local progression or metastasis (85% of cases) are needed. The pancreatic tumor microenvironment provides a rich source for novel drug targets. We aimed to identify and validate novel metabolic drug targets that are unique to hypoxic PDAC cells. Using bulk RNA sequencing in combination with metabolomics analyses in vitro, we previously found that PDAC cells negate the loss of intracellular unsaturated fatty acids in hypoxia by orchestrating the release of lysophospholipids (lyso-PLs) by cancer-associated fibroblasts, which are then taken up and stored in intracellular lipid droplets in hypoxic cancer cells. To confirm the relevance of these findings in vivo, we performed 3' droplet based single-cell RNA sequencing (scRNA-seq) combined with metabolomics analyses of intracellular and extracellular (tumor interstitial fluid) metabolites of MIAPaCa2 and patient-derived xenografts (PDX). Identification of cell lineages and subpopulations with hypoxic gene signatures was performed to correlate changes in metabolite levels with metabolic gene expression in vivo. This approach confirmed differential expression of lipid droplet-associated enzymes in hypoxic areas of the tumor, including lyso-PL acyl transferases (LPCAT1, LPCAT3), and phospholipases (LYPLA1, PLA2G15). We found that resistance of PDAC cell lines to pharmacologic treatment with inhibitors of fatty acid desaturases (FADS), reminiscent of hypoxia and nutrient starvation in vivo, was mediated by uptake of lyso-PLs from the medium. Importantly, genetic knockdown of LPCAT and LYPLA isoforms reversed the resistance to FADS inhibitors in culture in vitro and in vivo. Clinical relevance was demonstrated by mRNA expression analysis of PDAC patients from The Cancer Genome Atlas (TCGA) database, which showed that the expression of lyso-PL metabolizing genes is correlated with a significant worse prognosis (log-rank test, P=0.008). We are currently developing pharmacologic approaches to target LPCAT and LYPLA enzymes in hypoxic cancer cells as a novel approach for PDAC patients with unresectable disease.

Citation Format: Petrus R. de Jong, Marco Maruggi, Alejandro D. Campos, Morgan A. Brand, Robert Lemos, David A. Scott, Sally A. Litherland, J. Pablo Arnoletti, Brian P. James, Garth Powis. Targeting lysophospholipid metabolism inhibits pancreatic cancer cell proliferation under nutrient-limiting conditions [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2916.

JQ1 Induces DNA Damage and Apoptosis, and Inhibits Tumor Growth in a Patient-Derived Xenograft Model of Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a fatal disease with a 5-year survival of <30%. For a majority of patients, chemotherapy is the only therapeutic option, and virtually all patients relapse. Gemcitabine is the first-line agent for treatment of CCA. Patients treated with gemcitabine monotherapy survive ∼8 months. Combining this agent with cisplatin increases survival by ∼3 months, but neither regimen produces durable remissions. The molecular etiology of this disease is poorly understood. To facilitate molecular characterization and development of effective therapies for CCA, we established a panel of patient-derived xenograft (PDX) models of CCA. We used two of these models to investigate the antitumor efficacy and mechanism of action of the bromodomain inhibitor JQ1, an agent that has not been evaluated for the treatment of CCA. The data show that JQ1 suppressed the growth of the CCA PDX model CCA2 and demonstrate that growth suppression was concomitant with inhibition of c-Myc protein expression. A second model (CCA1) was JQ1-insensitive, with tumor progression and c-Myc expression unaffected by exposure to this agent. Also selective to CCA2 tumors, JQ1 induced DNA damage and apoptosis and downregulated multiple c-Myc transcriptional targets that regulate cell-cycle progression and DNA repair. These findings suggest that c-Myc inhibition and several of its transcriptional targets may contribute to the mechanism of action of JQ1 in this tumor type. We conclude that BET inhibitors such as JQ1 warrant further investigation for the treatment of CCA. Mol Cancer Ther; 17(1); 107-18. ©2017 AACR.

Abstract 2967: Pancreatic cancer cell growth requires lipids released by tumor-induced stroma autophagy

Pancreatic ductal adenocarcinoma (PDAC) is non-resectable in the majority of patients and highly resistant to chemotherapy, resulting in a poor survival. The tumor microenvironment and hypoxia are important modifiers of cancer progression in PDAC. Understanding the metabolic vulnerabilities of PDAC in the harsh tumor microenvironment may lead to novel therapeutic approaches with improved clinical efficacy. First, we found that PDAC cells showed beneficial effects of co-cultured stroma cells, but only under lipid-free serum conditions. To study the metabolic crosstalk between cancer cells and stroma in more detail, we performed an untargeted metabolomic screen of PDAC cells and fibroblasts co-cultured in normoxia and hypoxia, and performed RNA-seq profiling in parallel. We found that stromal cells are metabolically more responsive to co-culture than cancer cells. PDAC cells induce catabolic carbohydrate and protein metabolism in stromal cells, particularly in hypoxia. In contrast, 13C-based metabolic flux assays demonstrated that stromal cells display enhanced anabolic lipid metabolism in co-culture with PDAC cells. Furthermore, de novo synthesized 13C-labeled fatty acids in stromal cells were taken up by PDAC cells. In particular, PDAC cells showed extensive scavenging of lysophospholipids (lyso-PLs) from the culture medium, which was increased in co-culture under hypoxic conditions. These data were confirmed by analyzing portal vein plasma samples isolated from pancreatic cancer patients before and after surgery. In addition, we found metabolites and expression levels of metabolic enzymes from the glycerophospholipid pathway to be enriched in PDAC cells in co-culture and hypoxia. By using fibroblasts, human pancreatic stellate cells and patient-derived cancer-associated fibroblasts (CAFs), we demonstrate direct transfer of lyso-PLs from stromal to PDAC cells via lipid droplets. The transfer of lyso-PLs was abrogated by pharmacological inhibitors of autophagy, or by siRNA-mediated knockdown of autophagy genes in stromal and tumor cells. These data suggest that PDAC cells cause stroma cells to undergo autophagy, and reprogram stroma metabolism to obtain complex lipid species for their metabolic needs in the lipid-starved tumor microenvironment.

Citation Format: Petrus R. De Jong, Sean-Luc Shanahan, Morgan A. Brand, Alejandro D. Campos, Anagha Srirangam, Nikolas Marino, Claudia P. Miller, Olga Zagnitko, Adam D. Richardson, David A. Scott, Brian P. James, Andrew P. Hodges, Ally Perlina, Alexey M. Eroshin, Randall French, Malene Hansen, Sally A. Litherland, Andrew M. Lowy, J. Pablo Arnoletti, Garth Powis. Pancreatic cancer cell growth requires lipids released by tumor-induced stroma autophagy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2967. doi:10.1158/1538-7445.AM2017-2967

The BET bromodomain inhibitor JQ1 suppresses growth of pancreatic ductal adenocarcinoma in patient-derived xenograft models

The primary aim of this study was to evaluate the antitumor efficacy of the bromodomain inhibitor JQ1 in pancreatic ductal adenocarcinoma (PDAC) patient-derived xenograft (tumorgraft) models. A secondary aim of the study was to evaluate whether JQ1 decreases expression of the oncogene c-Myc in PDAC tumors, as has been reported for other tumor types. We used five PDAC tumorgraft models that retain specific characteristics of tumors of origin to evaluate the antitumor efficacy of JQ1. Tumor-bearing mice were treated with JQ1 (50 mg/kg daily for 21 or 28 days). Expression analyses were performed with tumors harvested from host mice after treatment with JQ1 or vehicle control. An nCounter PanCancer Pathways Panel (NanoString Technologies) of 230 cancer-related genes was used to identify gene products affected by JQ1. Quantitative RT-PCR, immunohistochemistry and immunoblots were carried out to confirm that changes in RNA expression reflected changes in protein expression. JQ1 inhibited the growth of all five tumorgraft models (P<0.05), each of which harbors a KRAS mutation; but induced no consistent change in expression of c-Myc protein. Expression profiling identified CDC25B, a regulator of cell cycle progression, as one of the three RNA species (TIMP3, LMO2 and CDC25B) downregulated by JQ1 (P<0.05). Inhibition of tumor progression was more closely related to decreased expression of nuclear CDC25B than to changes in c-Myc expression. JQ1 and other agents that inhibit the function of proteins with bromodomains merit further investigation for treating PDAC tumors. Work is ongoing in our laboratory to identify effective drug combinations that include JQ1.

Outcomes after implementing a tailored endoscopic step-up approach to walled-off necrosis in acute pancreatitis

BACKGROUND

The aim of the study was to compare the outcomes of patients with pancreatic or peripancreatic walled-off necrosis by endoscopy using the conventional approach versus an algorithmic approach based on the collection size, location and stepwise response to intervention.

METHODS

This was an observational before-after study of consecutive patients managed over two time intervals. In the initial period (2004-2009) symptomatic patients with walled-off necrosis underwent conventional single transmural drainage with placement of two stents and a nasocystic catheter, followed by direct endoscopic necrosectomy, if required. In the later period (2010-2013) an algorithmic approach was adopted based on size and extent of the walled-off necrosis and stepwise response to intervention. The main outcome was treatment success, defined as a reduction in walled-off necrosis size to 2 cm or less on CT after 8 weeks.

RESULTS

Forty-seven patients were treated in the first interval and 53 in the second. There was no difference in patient demographics, clinical or walled-off necrosis characteristics and laboratory parameters between the groups, apart from a higher proportion of women and Caucasians in the later period. The treatment success rate was higher for the algorithmic approach compared with conventional treatment (91 versus 60 per cent respectively; P < 0·001). On multivariable logistic regression, management based on the algorithm was the only predictor of treatment success (odds ratio 6·51, 95 per cent c.i. 2·19 to 19·37; P = 0·001).

CONCLUSION

An algorithmic approach to pancreatic and peripancreatic walled-off necrosis, based on the collection size, location and stepwise response to intervention, resulted in an improved rate of treatment success compared with conventional endoscopic management.

Abstract 4612: JQ1 suppresses tumor growth in tumorgraft models of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC), the most common form of pancreatic cancer, is one of the most deadly of malignancies. Patients often present late in the course of disease limiting treatment options, with the majority of patients receiving chemotherapy. However, currently available chemotherapy has not impacted overall patient survival, and new therapies are urgently needed.

Recently, our lab has documented that tumorgrafts derived specifically from primary PDAC tumors retain characteristics of the tumors of origin. In terms of drug evaluation, tumorgraft models have been shown to be predictive of clinical utility because these models retain tumor heterogeneity, recapitulate tumor architecture, and contain human stroma. To date, most efforts to use tumorgraft models to identify effective agents for the treatment of PDAC have taken an “all comers approach”; but this approach has thus far identified no effective therapies.

We proposed that JQ1, a compound that targets the oncogene c-Myc, would be efficacious for the treatment of PDAC, based on molecular characteristics of these tumors. The oncogene c-Myc is amplified or overexpressed in a 30-45% of primary or metastatic PDAC tumors. Also, overexpression of this oncogene is sufficient to induce tumor formation in a genetically engineered mouse model of PDAC, suggesting a critical role in the tumorigenesis of this tumor type. JQ1 is a novel compound in that it is a relatively specific bromodomain inhibitor. Bromodomain containing proteins recognize acetylated lysine residues on histones and direct the assembly of macromolecular molecules to the chromatin for transcription. A specific subfamily of these proteins, known as BETs (bromodomain and extra-terminal), recruit c-Myc to specific sites for transcription. Exposure of PDAC cells to JQ1 decreases the expression and therefore the activity of c-Myc.

To test the effectiveness of JQ1 in vivo, we administered 50 mg/kg of JQ1 i.p. once a day for 28 days and monitored tumor growth in a panel of 5 PDAC tumorgraft models. This dose and schedule of JQ1 administration was well tolerated in mice with no significant toxicity. Our data indicate that JQ1 suppressed tumor growth in all 5 models, compared to vehicle control treated mice. The data also showed a modest, JQ1-induced down regulation of c-Myc and NFkB. We conclude that JQ1 and other bromodomain inhibitors warrant further investigation as potentially effective agents for the treatment of PDAC.

This work was supported by UAB/UMN SPORE in pancreatic cancer (P50 CA101955).

Citation Format: Patrick L. Garcia, Tracy Gamblin, Leona N. Council, John D. Christein, J. Pablo Arnoletti, Martin J. Heslin, Joseph H. Richardson, Jun Qi, Jay E. Bradner, Karina J. Yoon. JQ1 suppresses tumor growth in tumorgraft models of pancreatic ductal adenocarcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4612. doi:10.1158/1538-7445.AM2014-4612

Recent developments in surgery: minimally invasive approaches for patients requiring pancreaticoduodenectomy

Over the past decade, minimally invasive surgery has been introduced as a means to allow manipulation of delicate tissues with outstanding visualization of the surgical field. The purpose of this article is to review the available literature regarding early postoperative outcomes and the technical challenges of minimally invasive pancreaticoduodenectomy, including robotic techniques. Herein, we provide a retrospective review of all published studies in the English literature in which a minimally invasive pancreaticoduodenectomy was performed. The reported advantages of minimally invasive pancreaticoduodenectomy include better visualization, faster recovery time, and decreased length of hospital stay. In cases of robotic approaches, some of the proposed advantages include increased dexterity and a superior ergonomic position for the operating surgeon. To our knowledge, few studies have reported results comparable to open techniques in oncologic outcomes with regard to the number of lymph nodes resected and clear margins obtained. An increasing number of pancreatic resections are being performed using minimally invasive approaches. It remains to be determined if the benefits of this technique outweigh its longer operative times and higher costs.

Beyond cytology: why and when does the oncologist require core tissue?

There are 2 main reasons why oncologists may require additional tissue and a histologic section in addition to cytopathology from FNA specimens: improved diagnostic accuracy and molecular characterization of tumors. Rather than mutually exclusive diagnostic procedures, EUS-FNA and EUS-CNB must be viewed as supplementary techniques and both approaches should be incorporated as essential tools in the current endoscopic armamentarium.

Development and histopathological characterization of tumorgraft models of pancreatic ductal adenocarcinoma

Pancreatic cancer is the one of the deadliest of all malignancies. The five year survival rate for patients with this disease is 3-5%. Thus, there is a compelling need for novel therapeutic strategies to improve the clinical outcome for patients with pancreatic cancer.  Several groups have demonstrated for other types of solid tumors that early passage human tumor xenograft models can be used to define some genetic and molecular characteristics of specific human tumors. Published studies also suggest that murine tumorgraft models (early passage xenografts derived from direct implantation of primary tumor specimens) may be useful in identifying compounds with efficacy against specific tumor types.  Because pancreatic cancer is a fatal disease and few well-characterized model systems are available for translational research, we developed and characterized a panel of pancreatic tumorgraft models for biological evaluation and therapeutic drug testing.  Of the 41 primary tumor specimens implanted subcutaneously into mice, 35 produced viable tumorgraft models.  We document the fidelity of histological and morphological characteristics and of KRAS mutation status among primary (F0), F1, and F2 tumors for the twenty models that have progressed to the F3 generation.  Importantly, our procedures produced a take rate of 85%, higher than any reported in the literature. Primary tumor specimens that failed to produce tumorgrafts were those that either contained <10% tumor cells or that were obtained from significantly smaller primary tumors. In view of the fidelity of characteristics of primary tumor specimens through at least the F2 generation in mice, we propose that these tumorgraft models represent a useful tool for identifying critical characteristics of pancreatic tumors and for evaluating potential therapies. 

Pancreatic Adenocarcinoma, version 2.2012: featured updates to the NCCN Guidelines

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Pancreatic Adenocarcinoma discuss the workup and management of tumors of the exocrine pancreas. These NCCN Guidelines Insights provide a summary and explanation of major changes to the 2012 NCCN Guidelines for Pancreatic Adenocarcinoma. The panel made 3 significant updates to the guidelines: 1) more detail was added regarding multiphase CT techniques for diagnosis and staging of pancreatic cancer, and pancreas protocol MRI was added as an emerging alternative to CT; 2) the use of a fluoropyrimidine plus oxaliplatin (e.g., 5-FU/leucovorin/oxaliplatin or capecitabine/oxaliplatin) was added as an acceptable chemotherapy combination for patients with advanced or metastatic disease and good performance status as a category 2B recommendation; and 3) the panel developed new recommendations concerning surgical technique and pathologic analysis and reporting.

Pancreatic Adenocarcinoma, version 2.2012: featured updates to the NCCN Guidelines

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Pancreatic Adenocarcinoma discuss the workup and management of tumors of the exocrine pancreas. These NCCN Guidelines Insights provide a summary and explanation of major changes to the 2012 NCCN Guidelines for Pancreatic Adenocarcinoma. The panel made 3 significant updates to the guidelines: 1) more detail was added regarding multiphase CT techniques for diagnosis and staging of pancreatic cancer, and pancreas protocol MRI was added as an emerging alternative to CT; 2) the use of a fluoropyrimidine plus oxaliplatin (e.g., 5-FU/leucovorin/oxaliplatin or capecitabine/oxaliplatin) was added as an acceptable chemotherapy combination for patients with advanced or metastatic disease and good performance status as a category 2B recommendation; and 3) the panel developed new recommendations concerning surgical technique and pathologic analysis and reporting.

Anal Carcinoma, Version 2.2012: featured updates to the NCCN guidelines

The workup and management of squamous cell anal carcinoma, which represents the most common histologic form of the disease, are addressed in the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Anal Carcinoma. These NCCN Guidelines Insights provide a summary of major discussion points of the 2012 NCCN Anal Carcinoma Panel meeting. In summary, the panel made 4 significant changes to the 2012 NCCN Guidelines for Anal Carcinoma: 1) local radiation therapy was added as an option for the treatment of patients with metastatic disease; 2) multifield technique is now preferred over anteroposterior-posteroanterior (AP-PA) technique for radiation delivery and the AP-PA technique is no longer recommended as the standard of care; 3) PET/CT should now be considered for radiation therapy planning; and 4) a section on risk reduction was added to the discussion section. In addition, the panel discussed the use of PET/CT for the workup of anal canal cancer and decided to maintain the recommendation that it can be considered in this setting. They also discussed the use of PET/CT for the workup of anal margin cancer and for the assessment of treatment response. They reaffirmed their recommendation that PET/CT is not appropriate in these settings.

Targeting ErbB3-mediated stromal-epithelial interactions in pancreatic ductal adenocarcinoma

Background:

We sought to investigate the role of ErbB3-mediated signalling on the interaction between pancreatic cancer-associated fibroblasts (CAF) and carcinoma cells in an effort to disrupt tumourigenic pancreatic ductal adenocarcinoma (PDAC) stromal–epithelial cross-communication.

Methods:

Primary CAF cultures were established from human PDAC surgical specimens. AsPC-1 pancreatic cancer cell murine subcutaneous xenografts were developed in the presence and absence of CAF and were subsequently treated with epidermal growth factor receptor (EGFR) inhibitors (erlotinib) and ErbB3 inhibitors (MM-121, monoclonal ErbB3 antibody).

Results:

Cancer-associated fibroblasts were found to secrete neuregulin-1 (NRG-1), which promoted proliferation via phosphorylation of ErbB3 and AKT in AsPC-1 PDAC cells. This signalling cascade was effectively inhibited both in vitro and in vivo by specific ErbB3 blockade with MM-121, with greater degree of tumourigenesis inhibition when combined with erlotinib. The CAF–AsPC-1 pancreatic cancer xenografts reached significantly greater tumour volume than those xenografts lacking CAF and were resistant to the anti-tumour effects of EGFR inhibition with erlotinib.

Conclusion:

Cancer-associated fibroblasts-derived NRG-1 promote PDAC tumourigenesis via ErbB3-AKT signalling and overcomes single-agent EGFR inhibition. Disruption of this stromally mediated tumourigenic mechanism is best obtained through combined EGFR-ErbB3 inhibition with both erlotinib and MM-121. We have identified the NRG-1/ErbB3 axis as an attractive molecular target for the interruption of tumourigenic stromal–epithelial interactions within the PDAC microenvironment.

A phase I study evaluating the role of the anti-epidermal growth factor receptor (EGFR) antibody cetuximab as a radiosensitizer with chemoradiation for locally advanced pancreatic cancer

PURPOSE

(1) To determine the safety of the epidermal growth factor receptor (EGFR) antibody cetuximab with concurrent gemcitabine and abdominal radiation in the treatment of patients with locally advanced adenocarcinoma of the pancreas. (2) To evaluate the feasibility of pancreatic cancer cell epithelial-mesenchymal transition (EMT) molecular profiling as a potential predictor of response to anti-EGFR treatment.

METHODS

Patients with non-metastatic, locally advanced pancreatic cancer were treated in this dose escalation study with gemcitabine (0-300 mg/m(2)/week) given concurrently with cetuximab (400 mg/m(2) loading dose, 250 mg/m(2) weekly maintenance dose) and abdominal irradiation (50.4 Gy). Expression of E-cadherin and vimentin was assessed by immunohistochemistry in diagnostic endoscopic ultrasound fine-needle aspiration (EUS-FNA) specimens.

RESULTS

Sixteen patients were enrolled in 4 treatment cohorts with escalating doses of gemcitabine. Incidence of grade 1-2 adverse events was 96%, and incidence of 3-4 adverse events was 9%. There were no treatment-related mortalities. Two patients who exhibited favorable treatment response underwent surgical exploration and were intraoperatively confirmed to have unresectable tumors. Median overall survival was 10.5 months. Pancreatic cancer cell expression of E-cadherin and vimentin was successfully determined in EUS-FNA specimens from 4 patients.

CONCLUSIONS

Cetuximab can be safely administered with abdominal radiation and concurrent gemcitabine (up to 300 mg/m(2)/week) in patients with locally advanced adenocarcinoma of the pancreas. This combined therapy modality exhibited limited activity. Diagnostic EUS-FNA specimens could be analyzed for molecular markers of EMT in a minority of patients with pancreatic cancer.

Epidermal growth factor receptor (EGFR) intron 1 polymorphism and clinical outcome in pancreatic adenocarcinoma

BACKGROUND

Epidermal growth factor receptor (EGFR) intron 1 has a polymorphic region of CA repeats that is believed to be associated with increased EGFR expression, tumor aggressiveness, and worse survival in cancer patients.

METHODS

A large population of pancreatic adenocarcinoma patients was investigated to evaluate this polymorphism as a potential prognostic marker of clinical outcome. Deoxyribonucleic acid obtained from 50 resected pancreatic adenocarcinomas and from 85 diagnostic endoscopic ultrasound-guided fine-needle aspiration procedures corresponding to patients with unresectable tumors was included. The correlation between CA repeat length and EGFR messenger ribonucleic acid levels was also examined.

RESULTS

Analysis of the 135 patients revealed no correlation between EGFR intron 1 CA repeat length and tumor stage. There was no difference in overall patient survival when stratified by allele length. A correlation between EGFR intron 1 length and EGFR transcript and protein levels could not be established.

CONCLUSIONS

The length of the EGFR intron 1 CA repeats does not correlate with levels of EGFR expression and cannot be used as marker of clinical prognosis in pancreatic cancer patients.

Abstract 1171: Gastrointestinal stromal tumors (GIST) cell proliferation inhibition with combined adenoviral and molecular targeted therapy

Introduction: GIST, the most common mesenchymal malignancies of the GI tract, are characterized by gain-of-function mutations in KIT and PDGFRα receptors. Imatinib and sunitinib are tyrosine kinase inhibitors (TKI) currently approved for the treatment of GIST. Recent evidence suggests that GIST cells acquire secondary resistance to TKI through activation of alternative signaling pathways. We hypothesize that gene therapy with replicative vector oncolysis (virotherapy) can be utilized to improve efficacy of TKI and overcome GIST resistance to treatment.

Objectives: To determine if a panel of oncolytic adenoviruses in combination with imatinib and sunitinib, results in synergistic inhibition of GIST cell proliferation.

Results: GIST882 and GIST-T1 cells were subjected to imatinib and sunitinib treatment in combination with a panel of oncolytic adenoviruses (Ad5, Ad5RGD, Ad5pK7, and Ad5 - Ad3 fiber knob), to assess their inhibitory effects on cell proliferation. The Ad5/3 vector had the best rate of gene transfer and cytolytic effect. The greatest anti-proliferative effects were observed with 100 viral particles/cell of the Ad5/3 vector combined with TKI concentrations of 0.1 µM in GIST-T1 cell line. The combination of TKI and oncolytic adenoviruses showed greater inhibition of GIST cell proliferation (78% decrease) when compared to TKI alone (58% decrease) and viral therapy alone (23% decrease, p&lt;0.01). Successful ex vivo infection and oncolysis of GIST by Ad5/3 particles was confirmed in cells obtained from patient surgical specimens (n=4).

Conclusions: The oncolytic adenovirus Ad5/3 infects and inhibits GIST cell proliferation both in vitro and ex vivo. Virotherapy with Ad5/3 has synergistic anti-proliferative effects with TKI and may help overcome GIST resistance to KIT targeted therapy.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1171.

Epigenetic downregulation of the DNA repair gene MED1/MBD4 in colorectal and ovarian cancer

MED1 is a base excision repair enzyme that interacts with the mismatch repair protein MLH1 and maintains genomic integrity by binding methylated DNA and repairing spontaneous deamination events. MED1 mutations have been associated with microsatellite instability and accelerated colorectal cancer (CRC) tumorigenesis. We propose that promoter methylation may serve as an alternative epigenetic mechanism for MED1 gene suppression during sporadic CRC tumorigenesis. Methylation status of the MED1 promoter was investigated in a panel of ovarian and colorectal cancer cell lines. The MED1 promoter region was sequenced following bisulfite treatment and sequence analysis identified a CpG island within the MED1 promoter which is frequently and preferentially methylated (> or =50%) in ovarian and colorectal cancer cell lines with low/reduced MED1 expression. In vitro reversal of methylation restored MED1 expression. In colorectal cancer patients, when MED1 methylation was present, both tumor and matched mucosa were affected equally (mean frequency of methylation 24%) and there was no correlation between methylation and tumor stage. Patients without history of CRC showed significantly lower frequency of methylation (mean 14%, p < 0.05). Decreased MED1 transcript levels were observed in matched normal mucosa when compared to controls (median fold difference 8.0). Additional decreased expression was seen between mucosa and matched tumor (median fold decrease 4.4). Thus, MED1 promoter methylation and gene silencing occur in sporadic CRC patients and represent an early event in CRC tumorigenesis. Detection of MED1 methylation and gene suppression in normal colon mucosa may contribute to identifying patients at higher risk of developing CRC during screening procedures.

Radiofrequency ablation for unresectable tumors of the liver

Surgical resection of primary or metastatic tumors of the liver offers patients the best long-term survival. Liver resections may not be appropriate in patients with bilobar metastases, liver dysfunction, or severe comorbidities. Radiofrequency ablation (RFA) is a technique used to destroy unresectable hepatic tumors through thermocoagulation. We retrospectively reviewed a consecutive series of patients undergoing RFA with unresectable hepatic tumors for local recurrence and overall survival. Under an Institutional Review Board-approved protocol, all patients treated with RFA at the University of Alabama at Birmingham from September 1, 1998, to June 15, 2005, were identified. During this time period, 189 lesions in 107 patients were treated with RFA. Patients' charts were retrospectively reviewed. Data is presented as mean +/- SEM. Significance is defined as P < 0.05. Patient demographics revealed 62 per cent males and 38 per cent females with a mean age of 59 (+/- 1) years. Hepatocellular carcinoma (HCC) represented 54 per cent of the tumors treated. Metastatic colorectal cancer represented 22 per cent and the remaining 24 per cent were other metastatic tumors. Overall recurrence rates for all tumors after RFA was 53 per cent. Local recurrence rates for HCC, colorectal cancer, and other metastatic lesions were 27.6 per cent, 29.1 per cent, and 52 per cent, respectively. The morbidity rate for the procedure was 11 per cent. There was one mortality (0.9%) related to RFA. Laparoscopic RFA for HCC in Childs-Pugh Class C cirrhotics (n = 6) resulted in 50 per cent of patients being transplanted with no evidence of disease at a mean follow-up period of 14 months. RFA is a safe and effective way for treating HCC and other unresectable tumors in the liver that are not eligible for hepatic resection. More effective control of systemic recurrence will dictate survival in the majority of patients with metastatic cancers. Local ablation for HCC in cirrhotic patients may be an effective bridge to transplantation. Liver transplantation may still be the most effective long-term treatment for localized HCC.

Radiofrequency Ablation for Unresectable Tumors of the Liver

Surgical resection of primary or metastatic tumors of the liver offers patients the best long-term survival. Liver resections may not be appropriate in patients with bilobar metastases, liver dysfunction, or severe comorbidities. Radiofrequency ablation (RFA) is a technique used to destroy unresectable hepatic tumors through thermocoagulation. We retrospectively reviewed a consecutive series of patients undergoing RFA with unresectable hepatic tumors for local recurrence and overall survival. Under an Institutional Review Board-approved protocol, all patients treated with RFA at the University of Alabama at Birmingham from September 1, 1998, to June 15, 2005, were identified. During this time period, 189 lesions in 107 patients were treated with RFA. Patients’ charts were retrospectively reviewed. Data is presented as mean ± SEM. Significance is defined as P < 0.05. Patient demographics revealed 62 per cent males and 38 per cent females with a mean age of 59 (±1) years. Hepatocellular carcinoma (HCC) represented 54 per cent of the tumors treated. Metastatic colorectal cancer represented 22 per cent and the remaining 24 per cent were other metastatic tumors. Overall recurrence rates for all tumors after RFA was 53 per cent. Local recurrence rates for HCC, colorectal cancer, and other metastatic lesions were 27.6 per cent, 29.1 per cent, and 52 per cent, respectively. The morbidity rate for the procedure was 11 per cent. There was one mortality (0.9%) related to RFA. Laparoscopic RFA for HCC in Childs-Pugh Class C cirrhotics (n = 6) resulted in 50 per cent of patients being transplanted with no evidence of disease at a mean follow-up period of 14 months. RFA is a safe and effective way for treating HCC and other unresectable tumors in the liver that are not eligible for hepatic resection. More effective control of systemic recurrence will dictate survival in the majority of patients with metastatic cancers. Local ablation for HCC in cirrhotic patients may be an effective bridge to transplantation. Liver transplantation may still be the most effective long-term treatment for localized HCC.

ErbB3 expression and dimerization with EGFR influence pancreatic cancer cell sensitivity to erlotinib

Abnormal expression and signaling of ErbB receptors has been implicated in multiple epithelial malignancies, including pancreatic cancer. Erlotinib, an epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), has been recently approved for pancreatic cancer treatment, but there are no reliable predictors of patient response. Expression of additional ErbB receptors seems to influence tumor response to EGFR-targeted therapy. We analyzed the influence of ErbB3 expression on pancreatic cancer cell response to erlotinib treatment. Proliferation assays of five human pancreatic cancer cell lines were performed following treatment with erlotinib. Expression and phosphorylation profiles of ErbB receptors and downstream adaptor protein (Akt, ERK1/2, STAT3, mTOR) were evaluated following stimulation with EGF or neuregulin-beta. The formation of EGFR homodimers and EGFR-ErbB3 heterodimers, necessary to enable ErbB3 downstream signaling, was demonstrated by chemical cross-linking assays. The effects of RNA inhibition of ErbB3 on sensitivity to erlotinib treatment were evaluated in AsPC-1 pancreatic cancer cells. Erlotinib inhibited Akt phosphorylation and proliferation of all the ErbB3-expressing cell lines but did not affect mTOR activation. Cross-linking studies confirmed the presence of EGFR-ErbB3 heterodimers in pancreatic cancer cells. Only the ErbB3-deficient MIA PaCa-2 cells displayed persistent Akt activation and ongoing proliferation in spite of erlotinib treatment. siRNA-mediated inhibition of ErbB3 expression in AsPC-1 cells resulted in acquired resistance to erlotinib treatment. Pancreatic cancer cells which lack ErbB3 do not display activation of the ErbB3-PI3K-Akt cascade induced by EGFR/ErbB3 heterodimers and become less critically dependent on EGFR signaling and therefore resistant to erlotinib. Pancreatic cancer expression of ErbB3 may be useful for EGFR-targeted therapy patient selection.

Pancreatic cancer epidermal growth factor receptor (EGFR) intron 1 polymorphism influences postoperative patient survival and in vitro erlotinib response

BACKGROUND

Epidermal growth factor receptor (EGFR) has a highly polymorphic CA repeat region that affects transcription efficiency and anti-EGFR drug sensitivity in carcinomas. Erlotinib is an EGFR tyrosine kinase inhibitor approved for pancreatic cancer treatment. We analyzed the impact of EGFR intron 1 CA repeat lengths in pancreatic cancer clinical outcome and in vitro response to erlotinib.

METHODS

Allele-specific EGFR intron 1 lengths were analyzed in 30 microdissected pancreatic cancer surgical specimens, matched peripheral blood samples, and 9 pancreatic cancer cell lines treated with erlotinib. CA repeat lengths were correlated with survival, tumor parameters, molecular markers of EGFR pathway activation, and in vitro antiproliferative effects of erlotinib.

RESULTS

Both patient samples and cell lines displayed the full spectrum of EGFR CA repeat lengths (14-22 per allele). Patients with shorter sum of total CA repeats (<36) had worse median survival than patients with >or=36 repeats (13.7 vs 30.6 months, P = .002). Shorter patient EGFR intron 1 length correlated with EGFR expression (P = .026). Tumor intron 1 length was identical to that of matched peripheral blood specimens. There was no correlation between EGFR intron 1 length and pancreatic cancer stage, nodal status, grade, or expression of p-EGFR, p-ERK and p-Akt. Shorter EGFR intron 1 length was associated with in vitro response to erlotinib treatment (P = .02).

CONCLUSIONS

Shorter EGFR intron 1 CA repeat length is associated with worse pancreatic cancer clinical prognosis and in vitro response to erlotinib. EGFR intron 1 length can be reliably measured in peripheral blood and may translate into a quantitative predictive marker of both pancreatic cancer aggressiveness and erlotinib sensitivity.

Surgical treatment of pancreatic endocrine neoplasms

BACKGROUND

Pancreatic endocrine neoplasia (PEN) is an entity with an indolent course and prolonged survival. The aim of the current study was to review the prognostic factors and outcome of patients with PEN at 1 institution.

METHODS

Records of patients with the diagnosis of PEN in the period of 1980 to 2001 were reviewed. Descriptive statistics and log-rank test were used; significance was defined as P < .05.

RESULTS

Of 49 patients, 25 had functional and 24 nonfunctional tumors. Surgery was performed in 43 patients, 36 with curative intent. With a median follow-up of 31 months, there were 5 deaths. Symptoms were controlled with surgical resection in 86%. Median disease-free survival (DFS) was 46 months; actuarial 5-year disease-specific (DSS) was 72%. Factors associated with better DFS and DSS were absence of liver involvement (P = .02) and resection of the primary tumor (P = .04).

CONCLUSIONS

Surgical resection and absence of liver metastases are associated with better DFS and DSS in patients with PEN.

Epidermal growth factor receptor (EGFR) is highly conserved in pancreatic cancer

BACKGROUND

Pancreatic cancer remains a deadly disease, and the vast majority of pancreatic cancer patients are not candidates for treatment with curative intent. Erlotinib, an EGFR-specific tyrosine kinase inhibitor, was approved recently for use in patients with pancreatic cancer. Somatic mutations in the EGFR gene appear to predict survival and response to tyrosine kinase inhibitor therapy in a subset of patients with non-small-cell lung cancer (NSCLC).

METHODS

The purpose of this study was to characterize EGFR mutations in pancreatic adenocarcinoma. EGFR TK mutations were analyzed in 9 pancreatic carcinoma cell lines and 31 clinical specimens from patients with pancreatic cancer who underwent resection. Using laser capture microdissection, tumor cells from patients were harvested selectively for genomic DNA extraction. Mutations were examined by direct sequencing of exons 18-21.

RESULTS

Of 9 pancreatic cancer cell lines, 6 had either 2454G>A or 2361G>A mutations in exon 20. Of 31 patients, 25 patients had 2361G>A in exon 20, and 1 patient had 2508C>T in exon 21. All were silent mutations.

CONCLUSIONS

The EGFR tyrosine kinase domain is highly conserved in pancreatic cancer. The association among EGFR mutation status, clinical prognosis, and response to anti-EGFR therapy described in NSCLC may not be applicable to pancreatic cancer. This observation does not diminish the possible role of anti-EGFR therapy in pancreatic cancer because there remains a need to explore alternative explanations for pancreatic cancer aberrant EGFR pathway activation such as ligand overexpression, gene amplification, and loss of inhibitory mechanisms.

Neoadjuvant and adjuvant therapy for rectal cancer

The currently available evidence from randomized clinical trials clearly supports the use of adjuvant therapy in general and preoperative combined modality therapy in particular as effective means of decreasing the rates of local recurrence, improving sphincter preservation rates, and probably im-proving overall survival when managing patients with locally advanced adenocarcinomas of the lower two thirds of the rectum. A radical surgical approach with adequately performed, sharp TME remains the standard of care for those patients. There is clearly a need to develop and validate surrogate biomarkers for the identification of patients who respond favorably to preoperative treatment. There is still a significant fraction of rectal cancer patients who ultimately die from their disease. The armamentarium of avail-able therapies is evolving rapidly, and hopefully local control rates and overall survival of rectal cancer patients will continue to improve in the near future.

Cyclooxygenase-2 expression and clinical outcome in gastrointestinal stromal tumors

The significance of cyclooxygenase-2 (COX-2) expression in mesenchymal tumors has not been completely described. We analyzed clinicopathologic variables and COX-2 protein expression in all mesenchymal tumors of the GI tract that were treated at our institution between 1990 and 2002. Paraffin-embedded specimens were immunohistochemically stained for KIT and COX-2 protein. KIT-positive tumors were diagnosed as gastrointestinal stromal tumors (GIST). Among 42 available specimens, 38 tumors were diagnosed as GIST and four were non-GIST mesenchymal GI tumors (KIT negative). The median overall survival for the GIST patients was 34 months. Ninety-two percent of GIST expressed COX-2 protein. COX-2 protein was not expressed in any of the non-GIST tumors. GIST patients with negative or low COX-2 expression developed disease recurrence and/or died of their disease in 37% of the cases, compared with 18% for GIST patients with high COX-2 expression (difference not statistically significant). The vast majority of mesenchymal tumors of the GI tract are GIST that express COX-2 protein. As opposed to known predictors of GIST behavior such as tumor size and mitotic count, levels of COX-2 protein expression did not correlate with clinical outcome.

Preoperative radiation therapy with selective dose escalation to the margin at risk for retroperitoneal sarcoma

BACKGROUND

Retroperitoneal sarcomas (RPSs) are rare tumors with poor survival rates due to difficult resectability and high local and distant recurrence rates. Preoperative radiation therapy appears to have dosimetric advantages to utilize the tumor as a tissue expander to limit exposure of small bowel to higher radiation doses.

METHODS

Between June 1999 and December 2003, 16 consecutive patients with biopsy-proven RPS were treated with preoperative radiation with selective dose escalation. This included 45 grays (Gy) in 25 fractions to the entire tumor plus margin and a boost dose of 57.5 Gy to the volume predicted as high risk for positive surgical margins. Treatment toxicity and local control were evaluated prospectively as primary endpoints. The secondary goal was the theoretical calculation of future dose escalation and feasibility. Each patient underwent laparotomy. Tumor response was judged using computed tomography (CT) scan and by necrosis on final pathology. Theoretical treatment plans evaluated the potential for additional radiation dose escalation.

RESULTS

All patients completed the radiation protocol. The most common acute side effects were nausea/vomiting, which affected 4 patients (25%), with only 1 patient requiring inpatient intravenous hydration. There was no severe late postoperative morbidity or mortality. Twelve tumors (75%) decreased in maximum dimension, with a median decrease of 9.4%. Fourteen of 16 patients (88%) underwent complete macroscopic resection. With a median follow-up of 28 months (range, 7-52 months), there were only 2 local recurrences. The actuarial 2-year local control rate was 80%. Theoretical treatment plans suggest that significant dose escalation (up to 80 Gy) may be possible.

CONCLUSIONS

Preoperative radiation therapy with selective dose escalation to the margin at risk is tolerable and allows higher radiation dose to the volume judged to be at greatest risk for local tumor recurrence.

Tumor-associated down-regulation of 15-lipoxygenase-1 is reversed by celecoxib in colorectal cancer

OBJECTIVE

To evaluate the role of celecoxib on 15-lipoxygenase-1 (15-LOX-1) expression, protein levels, and rates of apoptosis in colorectal cancer cell lines. Also, to evaluate the expression of 15-LOX-1 in human normal mucosa, adenoma, and carcinoma with correlation to overall survival.

SUMMARY BACKGROUND DATA

The function of 15-LOX-1 is to maintain normal rates of apoptosis (programmed cell death). Decreased apoptosis is one mechanism of cancer growth and dissemination. It is our hypothesis that expression of 15-LOX-1 is reduced in human colorectal cancer (CRC) and the administration of celecoxib can reverse this process and induce apoptosis.

METHODS

Effect of celecoxib in cell culture: The effect of 40 micromol/L celecoxib was compared with untreated controls in tissue culture utilizing HT-29 and DLD-1 CRC cell lines. Expression of 15-LOX-1 protein was measured by immunoblot. Induction of apoptosis was evaluated by annexin V staining. All data are presented as mean +/- SEM, with significance defined as P < 0.05. 15-LOX-1 in human CRC: From February 1998 to January 2002, 126 patients underwent surgical resection of either colorectal adenomas (n = 24) or carcinomas (n = 102), or both (n = 25). Tissue was macrodissected, snap frozen, and stored at -80 degrees C. After tissue processing, RNA was extracted and gene expression of 15-LOX-1 was quantified utilizing ABI prism real-time quantitative RT-PCR. Significance evaluated by the Wilcoxon signed rank test.

RESULTS

Effect of celecoxib in cell culture: After 72 hours of treatment with celecoxib, immunoblot demonstrated a 1.5- to 2-fold increase in 15-LOX-1 protein expression in HT-29 and DLD-1 cells, respectively. Celecoxib produced greater than a 2-fold increase in the rate of apoptosis compared with control cells in both cell lines (P < 0.05). 15-LOX-1 in human CRC: The mean age of the patients was 62 +/- 1 years; 78% were white and 48% were female. The mean size of the polyps and cancers were 3.0 +/- 0.4 and 5.0 +/- 0.1 cm, respectively. Expression of 15-LOX-1 relative to S9 was 30 in normal mucosa and significantly down-regulated to 11 in adenomas and 16 in carcinomas (P < 0.05).

CONCLUSIONS

15-LOX-1 gene expression is significantly reduced in both human colorectal adenomas and carcinomas and associated with decreased survival. Administration of celecoxib restores 15-LOX-1 protein expression and induces apoptosis. Down-regulation of 15-LOX-1 is an early event in the adenoma to carcinoma sequence, and reversal with celecoxib may represent one mechanism for chemoprevention of polyps or treatment of carcinomas.

Differential stromal and epithelial localization of cyclooxygenase-2 (COX-2) during colorectal tumorigenesis

The purpose of the following study is to describe the localization of COX-2 protein and COX-2 mRNA during human colorectal tumorigenesis and to identify potential cellular targets for COX-2 inhibition in chemopreventive strategies. Immunohistochemistry with digital image analysis was used to determine COX-2 protein expression in histologic sections containing synchronous normal colorectal mucosa, adenomas and carcinomas, from 17 previously untreated patients. Epithelial and stromal COX-2 mRNA expression was analyzed by reverse transcription-polymerase chain reaction (RT-PCR), on laser-capture microdissected samples from the same histologies. The stromal compartment in normal colorectal mucosa and adenomas showed higher levels of COX-2 protein expression compared to colorectal carcinomas (p < .0001). Conversely, epithelial COX-2 protein was significantly increased only after development of the invasive phenotype (p < .0001). RT-PCR demonstrated higher stromal COX-2 mRNA expression compared to that within the epithelium for colorectal adenomas and carcinomas. In conclusion, stromal COX-2 may be the target for chemopreventive agents in the early stages of colorectal carcinogenesis.

Analysis of KIT Mutations in Sporadic and Familial Gastrointestinal Stromal Tumors: Therapeutic Implications through Protein Modeling

PURPOSE

Gastrointestinal stromal tumors (GIST) are characterized by expressing a gain-of-function mutation in KIT, and to a lesser extent, PDGFR. Imatinib mesylate, a tyrosine kinase inhibitor, has activity against GISTs that contain oncogenic mutations of KIT. In this study, KIT and PDGFRalpha mutation status was analyzed and protein modeling approaches were used to assess the potential effect of KIT mutations in response to imatinib therapy.

EXPERIMENTAL DESIGN

Genomic DNA was isolated from GIST tumors. Exons 9, 11, 13, and 17 of c-KIT and exons 12, 14, and 18 of PDGFRalpha were evaluated for oncogenic mutations. Protein modeling was used to assess mutations within the juxtamembrane region and the kinase domain of KIT.

RESULTS

Mutations in KIT exons 9, 11, and 13 were identified in GISTs with the majority of changes involving the juxtamembrane region of KIT. Molecular modeling indicates that mutations in this region result in disruption of the KIT autoinhibited conformation, and lead to gain-of-function activation of the kinase. Furthermore, a novel germ-line mutation in KIT was identified that is associated with an autosomal dominant predisposition to the development of GIST.

CONCLUSIONS

We have used protein modeling and structural analyses to elucidate why patients with GIST tumors containing exon 11 mutations are the most responsive to imatinib mesylate treatment. Importantly, mutations detected in this exon and others displayed constitutive activation of KIT. Furthermore, we have found tumors that are both KIT and PDGFRalpha mutation negative, suggesting that additional, yet unidentified, abnormalities may contribute to GIST tumorigenesis.

Mechanisms of resistance to Erbitux (anti-epidermal growth factor receptor) combination therapy in pancreatic adenocarcinoma cells

We previously demonstrated that pancreatic adenocarcinoma BxPC-3 xenografts display resistance to treatment with Erbitux, gemcitabine, and radiation, whereas MIA PaCa-2 xenografts are highly sensitive to the same therapy. Here, we elucidate in vitro mechanisms that may explain the observed differential response of epidermal growth factor receptor (EGFR) expressing pancreatic adenocarcinoma xenografts to Erbitux-based combination therapy in vivo. MIA PaCa-2 and BxPC-3 protein lysates were probed with antibodies to EGFR, ErbB2, ErbB3, and ErbB4. Constitutive ErbB3 activity was visualized by immunoblot analysis using anti-phosphotyrosine antibodies and receptor-specific immunoprecipitates. erbB2 and erbB3 gene expression in both cell lines was quantified with real-time polymerase chain reaction. Erbitux-induced internalization of EGFR was determined by flow cytometry following Erbitux treatment for different incubation times at 0 degrees C and 37 degrees C. MIA PaCa-2 and BxPC-3 protein extracts were also probed with anti-phospho-mitogen-activated protein kinase antibody after stimulation with EGF and in the presence of Erbitux. Although both cell lines expressed EGFR and ErbB2 protein, ErbB3 protein was selectively expressed by BxPC-3 cells, where it also showed evidence of constitutive phosphorylation. There was a 10-fold increase of erbB3 transcript levels in BxPC-3 cells compared with MIA PaCa-2. ErbB4 protein was not detectable in either cell line. Erbitux mediated EGFR internalization in MIA PaCa-2 cells after 2 hours of incubation, whereas it did not promote EGFR internalization in BxPC-3 cells. Likewise, EGF-dependent phosphorylation of MAPK p44/42 was blocked by Erbitux treatment in MIA PaCa-2 but not BxPC-3 cells. Erbitux selectively interfered with EGF-induced MAPK activation in MIA PaCa-2 but not BxPC-3 cells. Persistent MAPK activation and impaired in vitro internalization of EGFR by BxPC-3 pancreatic cancer cells may be due to constitutive ErbB3 signaling, facilitated by heterodimerization with EGFR, which may explain resistance to Erbitux-based combination therapy in vivo.

Heparin-induced thrombocytopenia in coronary bypass surgery

We report on a 51-year-old man with severe two-vessel coronary disease and an ejection fraction of 15% who presented with myocardial ischemia and heparin-induced thrombocytopenia after coronary angioplasty. Before coronary bypass surgery, the antithrombin agent argatroban was used for anticoagulation and an intraaortic balloon pump was inserted. Direct coronary bypass surgery was performed to the left anterior descending artery and to the posterior descending artery using the 'Octopus' tissue stabilization device (Manfrotto, Feltre, Italy). The postoperative course was uneventful and associated with normal platelet counts. The patient was discharged on the 6th postoperative day.

Surgical treatment of benign hepatic mass lesions

Benign hepatic mass lesions may require surgical treatment for symptomatic relief or prevention of hemorrhage. The most common benign hepatic mass lesions in the United States are hemangioma, focal nodular hyperplasia, hepatic adenoma, and congenital liver cyst. We report a series of liver resections performed for benign hepatic masses at our institution. All liver resections were performed with total inflow occlusion during the parenchymal transection time. None of our patients received perioperative blood products. No postoperative complications occurred, and the average length of hospital stay was 6 days. Surgeons performing hepatic resections for benign mass lesions should be able to complete these procedures with low operative blood loss and low operative morbidity.

Early postoperative complications of splenectomy for hematologic disease

Splenectomy may be indicated in a variety of hematologic diseases for diagnostic reasons, therapeutic reasons, or both. Most reviews reveal a high proportion of procedures performed as part of the staging process for Hodgkin disease. Splenectomy for myelofibrosis has been associated with an increased postoperative complication rate. Other determinants of morbidity have been splenic weight and operative blood loss. The authors reviewed a series of 83 adult patients from a prospective database established in 1991 to determine the incidence of early postoperative complications associated with splenectomy for hematologic disease and to analyze patient characteristics that may predict their occurrence. Morbidity that occurred within 30 days of splenectomy was considered to be an early postoperative complication. Operative estimated blood loss and incidence of postoperative complications were correlated with patient age, preoperative platelet count, splenic weight, and diagnosis of myelofibrosis as regression covariates. Indications for splenectomy were therapeutic in 76 patients (92%). Median splenic weight was 760 g, and 22 patients had massive splenomegaly. Patients with splenic weight more than 1,500 g had a significantly higher median estimated blood loss (300 ml; p = 0.02). Splenic weight was the main determinant of estimated blood loss in a multiple linear regression analysis (p = 0.02). Twenty-two patients (27%) experienced postoperative complications and five of those patients died (6%). Patients with myelofibrosis had the highest incidence of complications (50%) and the highest postoperative mortality (21%; p = 0.04). In a logistic regression model, estimated blood loss was the only variable significantly correlated with postoperative complications (p = 0.02). Splenectomy for hematologic disease is associated with an acceptable early postoperative complication rate, even when the indication is predominantly therapeutic. Patients at particularly high risk include those with elevated operative blood loss, massive splenomegaly, and myelofibrosis.

Reduction of transfusion requirements during major hepatic resection for metastatic disease

BACKGROUND

Our purpose was to determine whether the combination of total liver vascular inflow occlusion (Pringle maneuver) and rapid hepatic transection with a clamp-crush technique results in significant reduction of blood loss and transfusion requirements during major hepatic resections.

METHODS

A series of 49 adult patients underwent major hepatic resections for metastatic disease between April 1, 1992, and March 31, 1998. Group 1 patients (n = 15) had standard hilar dissection and finger-fracture hepatic transection without total liver inflow occlusion. Group 2 patients (n = 34) had total liver inflow occlusion and clamp-crush parenchymal transection.

RESULTS

Median blood loss was 1600 mL for group 1 and 500 mL for group 2 (P = .001). Eleven (73%) patients in group 1 required intraoperative blood transfusion (median 2 units) compared with 7 (21%) in group 2 with a median of 0 units (P = .001 and P < .001, respectively). Of the 7 patients in group 2 who required transfusion, 3 had a preoperative hemoglobin below 10 g/dL, 1 required splenectomy for operative injury, and 1 underwent a concomitant complicated small bowel resection.

CONCLUSIONS

Major hepatic resections can be performed without transfusion of blood products when preoperative hemoglobin is above 10 g/dL and concomitant major surgical procedures are not required.

Reduction of transfusion requirements during major hepatic resection for metastatic disease

BACKGROUND

Our purpose was to determine whether the combination of total liver vascular inflow occlusion (Pringle maneuver) and rapid hepatic transection with a clamp-crush technique results in significant reduction of blood loss and transfusion requirements during major hepatic resections.

METHODS

A series of 49 adult patients underwent major hepatic resections for metastatic disease between April 1, 1992, and March 31, 1998. Group 1 patients (n = 15) had standard hilar dissection and finger-fracture hepatic transection without total liver inflow occlusion. Group 2 patients (n = 34) had total liver inflow occlusion and clamp-crush parenchymal transection.

RESULTS

Median blood loss was 1600 mL for group 1 and 500 mL for group 2 (P = .001). Eleven (73%) patients in group 1 required intraoperative blood transfusion (median 2 units) compared with 7 (21%) in group 2 with a median of 0 units (P = .001 and P < .001, respectively). Of the 7 patients in group 2 who required transfusion, 3 had a preoperative hemoglobin below 10 g/dL, 1 required splenectomy for operative injury, and 1 underwent a concomitant complicated small bowel resection.

CONCLUSIONS

Major hepatic resections can be performed without transfusion of blood products when preoperative hemoglobin is above 10 g/dL and concomitant major surgical procedures are not required.

Thrombospondin and transforming growth factor-beta 1 increase expression of urokinase-type plasminogen activator and plasminogen activator inhibitor-1 in human MDA-MB-231 breast cancer cells

BACKGROUND

Thrombospondin is a high molecular weight adhesive glycoprotein that has been shown to function in mechanisms of tumor progression. The authors' previous studies have shown that thrombospondin promotes human lung carcinoma invasion by up-regulation of the plasminogen activator system through a mechanism involving the activation of transforming growth factor-beta 1 (TGF-beta 1). In this study, a similar thrombospondin-mediated mechanism operative in breast carcinoma cells is described.

METHODS

The effect of thrombospondin and TGF-beta 1 on the capacity of a line of breast carcinoma cells to activate plasminogen was measured as well as the physiologic consequences of these activities on cell adhesion and proliferation. Plasminogen activation was assessed by measuring the plasmin activity and plasminogen activator inhibitor-1 (PAI-1) levels in cell-conditioned media and the cell-associated urokinase-type plasminogen activator (uPA) levels.

RESULTS

Treatment of MDA-MB-231 breast carcinoma cells with either thrombospondin or TGF-beta 1 caused increased secretion of PAI-1 with a concomitant decrease in plasmin activity, whereas cell-associated uPA expression was increased with respect to controls. Thrombospondin (40 micrograms/ml) or TGF-beta 1 (5 ng/ml) stimulated the cells to secrete 5.5- and 6.7-fold more PAI-1 than controls, respectively, and caused decreased plasmin activity in the cell culture medium. Conversely, either thrombospondin (40 micrograms/ml) or TGF-beta 1 (5 ng/ml) caused the cells to express 4.55- and 5.38-fold more uPA than controls, respectively. Thrombospondin and TGF-beta 1 induced a more flattened and spread appearance in the cells with no effect on proliferation. These effects could be reversed with antibodies to either thrombospondin or TGF-beta 1 and were not due to contamination of thrombospondin with active TGF-beta 1.

CONCLUSIONS

Thrombospondin and TGF-beta 1 function similarly to increase cell-associated uPA and cell-secreted PAI-1. These data suggest that thrombospondin may not only function as an adhesive molecule, but through a mechanism involving the activation of TGF-beta 1, may modulate cell surface protease expression. In addition, these observations suggest that thrombospondin and TGF-beta 1 could promote metastasis by increasing uPA-mediated cell invasion, whereas through the action of PAI-1, also protect blood-born tumor emboli from destruction by host fibrinolytic enzymes.

Computer-assisted image analysis of tumor sections for a new thrombospondin receptor

BACKGROUND

A cell surface receptor (50 kd) has been recently identified in malignant cells that recognizes the tumor cell adhesive domain (ie, cysteine-serine-valine-threonine-cysteine-glycine [CSVTCG]) of thrombospondin (TSP). This CSVTCG-specific TSP receptor can be considered as a new tumor marker, and its concentration on the cell surface may correlate directly with the capacity of tumor cells to invade and metastasize.

MATERIALS AND METHODS

Six patients with primary, stages III and IV squamous cell carcinomas of the head and neck were studied. Tumor sections were specifically stained for this receptor with immunohistochemical techniques. The stained specimens were then subjected to computer-assisted image analysis. The area of positive staining and the heterogeneity of the pattern of staining were compared to peritumoral angiogenesis and clinical outcome of the patients.

RESULTS

The results indicate that those patients with a high and homogenous positive stain score (mean +/- standard error [SE] 78 +/- 5%) for the CSVTCG-specific TSP receptor had high microvessel density and died from metastatic disease within 12 months of initial treatment (correlation coefficients = 0.95 and 1, respectively). Patients with a low and heterogenous positive stain score for receptor (mean +/- SE 8 +/- 2%; P < 0.001) had low microvessel counts and remained disease-free for at least 2 years. There was no relationship between receptor density and histologic classification of the primary tumors.

CONCLUSION

The CSVTCG-specific TSP receptor, quantified through image analysis of immunohistochemical stained tissue sections, is highly predictive of clinical outcome in patients with squamous cell carcinomas of the head and neck.

Thrombospondin (TSP) and transforming growth factor beta 1 (TGF-beta) promote human A549 lung carcinoma cell plasminogen activator inhibitor type 1 (PAI-1) production and stimulate tumor cell attachment in vitro

A growing body of evidence has recently implicated TSP and TGF-beta in the process of malignancy, such as tumor cell proliferation, tumor angiogenesis, and metastasis. The purpose of the present study was to evaluate potential mechanisms of TSP and TGF-beta in tumor cell attachment and invasion. Our results indicate that both TSP and TGF-beta promoted tumor cell attachment and spreading in the presence of plasminogen. The mechanism for these effects appeared to be due, in part, to the capacity of TSP and TGF-beta to induce tumor cell production of (PAI-1). PAI-1, which is a natural inhibitor of tumor-cell associated urokinase-type plasminogen activator (uPA) activity, inhibited activation of plasminogen to plasmin in the growth media, thereby preventing plasmin-induced detachment of cells. The TSP-promoted production of PAI-1 could be inhibited not only by anti-TSP antibodies but also by a neutralizing antibody against TGF-beta. These results suggest that TSP by a mechanism involving TGF-beta can promote cell adhesion through stimulation of tumor cell secretion of PAI-1. These data provide evidence that TSP not only has the capacity of functioning as a matrix protein to directly promote cell-substratum adhesion but that TSP can also stimulate cell adhesion and spreading by modulating cell surface protease expression through stimulation of tumor-associated production of PAI-1.