Overexpression of HER2/neu oncogene in pancreatic cancer correlates with shortened survival

Evaluation of HER2Neu Status in Periampullary Cancers in Tertiary Care Centre in Northern India: A Three-Year Retrospective Study

Background Periampullary carcinoma is a heterogeneous group of malignancies, and despite advances in treatment, its mortality rate remains high. A better understanding of the disease and factors influencing its course and potential therapeutic targets is imperative for improving its overall outcome. Through comprehensive cytogenetic analysis, it has been established that the development of periampullary carcinogenesis involves specific chromosomal aberrations, dysregulation of oncogenes, and suppression of genes in a multistep progressive manner. Our study aimed to evaluate the expression of human epidermal growth factor (HER2Neu) in periampullary cancers using immunohistochemistry and fluorescent in situ hybridization. Material and methods This was a retrospective study in which all consecutive cases of periampullary carcinoma diagnosed over a period of three years were evaluated. HER2neu expression was analyzed using immunohistochemistry (IHC) and fluorescent in-situ hybridization (FISH). Histopathological evaluation was performed according to the College of American Pathologists (CAP) protocol. Results Twenty patients were diagnosed during the study period. On histomorphologic analysis, most cases (n=17) were diagnosed as well-differentiated adenocarcinomas, the most common subsite being the ampulla of Vater and pathological staging as pT2N0Mx. On IHC, no overexpression of HER2Neu was reported in any case, but FISH analysis revealed one point of amplification with HER/centromere enumerator probe (CEP) ratio>2. Conclusion HER2Neu evaluation in periampullary carcinoma has limited value; thus, it could have a restricted therapeutic role.

Dual Targeting of the EGFR/HER2 Pathway in Combination with Systemic Chemotherapy in Refractory Pancreatic Cancer-The CONKO-008 Phase I Investigation

Background: Primary objective of this present trial was to define the maximum tolerable dose of lapatinib in combination with oxaliplatin, 5-fluorouracil, and folinic acid (OFF) in refractory pancreatic cancer. The secondary objective was to assess the safety and efficacy of lapatinib plus OFF. Methods: We conducted a phase I trial using an accelerated dose escalation design in patients with refractory pancreatic cancer. Lapatinib was given on days 1 to 42 in combination with folinic acid 200 mg/m² day + 5-fluorouracil 2000 mg/m² (24 h) on days 1, 8, 15, and 22, and oxaliplatin 85 mg/m² days 8 and 22 of a 43-day cycle (OFF). Toxicity and efficacy were evaluated. Results: In total, eighteen patients were enrolled: dose level 1 (1000 mg) was assigned to seven patients, dose level 2 (1250 mg), five patients; and dose level 3 (1500 mg), six patients. Dose-limiting toxicities were diarrhea and/or neutropenic enterocolitis observed in two of six patients: one diarrhea III°, one diarrhea IV°, as well as neutropenic enterocolitis. The maximum tolerable dose of lapatinib was 1250 mg OD. Conclusions: The combination of lapatinib 1250 mg OD with platinum-containing chemotherapy is safe and feasible in patients with refractory pancreatic cancer and warrants further investigation.

Macrophages-induced IL-18-mediated eosinophilia promotes characteristics of pancreatic malignancy

The current study presents first CP murine model that show IL-18–induced eosinophil inflammation-mediated induction of oncogenic proteins and several pathological malignant characteristics.

Reports indicate that accumulated macrophages in the pancreas are responsible for promoting the pathogenesis of chronic pancreatitis (CP). Recently, macrophage-secreted cytokines have been implicated in promoting pancreatic acinar-to-ductal metaplasia (ADM). This study aims to establish the role of accumulated macrophage-activated NLRP3-IL-18-eosinophil mechanistic pathway in promoting several characteristics of pancreatic malignancy in CP. We report that in a murine model of pancreatic cancer (PC), accumulated macrophages are the source of NLRP3-regulated IL-18, which promotes eosinophilic inflammation-mediated accumulation to periductal mucin and collagen, including the formation of ADM, pancreatic intraepithelial neoplasia (PanINs), and intraductal papillary mucinous neoplasm. Most importantly, we show improved malignant characteristics with reduced levels of oncogenes in an anti–IL-18 neutralized and IL-18 gene deficient murine model of CP. Last, human biopsies validated that NLRP3-IL-18–induced eosinophils accumulate near the ducts, showing PanINs formation in PC. Taken together, we present the evidence on the role of IL-18–induced eosinophilia in the development of PC phenotype like ADM, PanINs, and ductal cell differentiation in inflammation-induced CP.

Immunotherapy and pancreatic cancer: unique challenges and potential opportunities

Despite decades of research, pancreatic ductal adenocarcinoma (PDAC) continues to have the worst 5-year survival of any malignancy. With 338,000 new cases diagnosed and over 300,000 deaths per year globally there is an urgent unmet need to improve the therapeutic options available.

Novel immunotherapies have shown promising results across multiple solid tumours, in a number of cases surpassing chemotherapy as a first-line therapeutic option. However, to date, trials of single-agent immunotherapies in PDAC have been disappointing and PDAC has been labelled as a nonimmunogenic cancer. This lack of response may in part be attributed to PDAC’s unique tumour microenvironment (TME), consisting of a dense fibrotic stroma and a scarcity of tumour infiltrating lymphocytes. However, as our understanding of the PDAC TME evolves, it is becoming apparent that the problem is not simply the immune system failing to recognize the cancer. There is a highly complex interplay between stromal signals, the immune system and tumour cells, at times possibly restraining tumour growth and at others supporting growth and metastasis.

Understanding this complexity will enable the development of rational combinations with immunotherapy, priming the TME to offer immunotherapy the best chance of success. This review seeks to describe the unique challenges of the PDAC TME, the potential opportunities it may afford and the trials in progress capitalizing on recent insights in this area.

Strategies for Increasing Pancreatic Tumor Immunogenicity

Immunotherapy has changed the standard of care for multiple deadly cancers, including lung, head and neck, gastric, and some colorectal cancers. However, single-agent immunotherapy has had little effect in pancreatic ductal adenocarcinoma (PDAC). Increasing evidence suggests that the PDAC microenvironment is comprised of an intricate network of signals between immune cells, PDAC cells, and stroma, resulting in an immunosuppressive environment resistant to single-agent immunotherapies. In this review, we discuss differences between immunotherapy-sensitive cancers and PDAC, the complex interactions between PDAC stroma and suppressive tumor-infiltrating cells that facilitate PDAC development and progression, the immunologic targets within these complex networks that are druggable, and data supporting combination drug approaches that modulate multiple PDAC signals, which should lead to improved clinical outcomes. Clin Cancer Res; 23(7); 1656-69. ©2017 AACRSee all articles in this CCR Focus section, "Pancreatic Cancer: Challenge and Inspiration."

HER2/HER3 pathway in biliary tract malignancies; systematic review and meta-analysis: a potential therapeutic target?

Human epidermal growth factor receptor 2 (HER2) overexpression and amplification have been reported as predictive markers for HER2-targeted therapy in breast and gastric cancer, whereas human epidermal growth factor receptor 3 (HER3) is emerging as a potential resistance factor. The aim of this study was to perform a systematic review and meta-analysis of the HER2 and HER3 overexpression and amplification in biliary tract cancers (BTCs). An electronic search of MEDLINE, American Society of Clinical Oncology (ASCO), European Society of Medical Oncology Congress (ESMO), and American Association for Cancer Research (AACR) was performed to identify studies reporting HER2 and/or HER3 membrane protein expression by immunohistochemistry (IHC) and/or gene amplification by in situ hybridization (ISH) in BTCs. Studies were classified as "high quality" (HQ) if IHC overexpression was defined as presence of moderate/strong staining or "low quality" (LQ) where "any" expression was considered positive. Of 440 studies screened, 40 met the inclusion criteria. Globally, HER2 expression rate was 26.5 % (95 % CI 18.9-34.1 %). When HQ studies were analyzed (n = 27 studies), extrahepatic BTCs showed a higher HER2 overexpression rate compared to intrahepatic cholangiocarcinoma: 19.9 % (95 % CI 12.8-27.1 %) vs. 4.8 % (95 % CI 0-14.5 %), respectively, p value 0.0049. HER2 amplification rate was higher in patients selected by HER2 overexpression compared to "unselected" patients: 57.6 % (95 % CI 16.2-99 %) vs. 17.9 % (95 % CI 0.1-35.4 %), respectively, p value 0.0072. HER3 overexpression (4/4 HQ studies) and amplification rates were 27.9 % (95 % CI 9.7-46.1 %) and 26.5 % (one study), respectively. Up to 20 % of extrahepatic BTCs appear to be HER2 overexpressed; of these, close to 60 % appear to be HER2 amplified, while HER3 is overexpressed or amplified in about 25 % of patients. Clinical relevance for targeted therapy should be tested in prospective clinical trials.

Molecular Drivers of Pancreatic Cancer Pathogenesis: Looking Inward to Move Forward

Pancreatic cancer (PC) continues to rank among the most lethal cancers. The consistent increase in incidence and mortality has made it the seventh leading cause of cancer-associated deaths globally and the third in the United States. The biggest challenge in combating PC is our insufficient understanding of the molecular mechanism(s) underlying its complex biology. Studies during the last several years have helped identify several putative factors and events, both genetic and epigenetic, as well as some deregulated signaling pathways, with implications in PC onset and progression. In this review article, we make an effort to summarize our current understanding of molecular and cellular events involved in the pathogenesis of pancreatic malignancy. Specifically, we provide up-to-date information on the genetic and epigenetic changes that occur during the initiation and progression of PC and their functional involvement in the pathogenic processes. We also discuss the impact of the tumor microenvironment on the molecular landscape of PC and its role in aggressive disease progression. It is envisioned that a better understanding of these molecular factors and the mechanisms of their actions can help unravel novel diagnostic and prognostic biomarkers and can also be exploited for future targeted therapies.

Understanding the Impact of ErbB Activating Events and Signal Transduction on Antigen Processing and Presentation: MHC Expression as a Model

Advances in molecular pathology have changed the landscape of oncology. The ability to interrogate tissue samples for oncogene amplification, driver mutations, and other molecular alterations provides clinicians with an enormous level of detail about their patient's cancer. In some cases, this information informs treatment decisions, especially those related to targeted anti-cancer therapies. However, in terms of immune-based therapies, it is less clear how to use such information. Likewise, despite studies demonstrating the pivotal role of neoantigens in predicting responsiveness to immune checkpoint blockade, it is not known if the expression of neoantigens impacts the response to targeted therapies despite a growing recognition of their diverse effects on immunity. To realize the promise of 'personalized medicine', it will be important to develop a more integrated understanding of the relationships between oncogenic events and processes governing anti-tumor immunity. One area of investigation to explore such relationships centers on defining how ErbB/HER activation and signal transduction influences antigen processing and presentation.

Eosinophil peroxidase activates cells by HER2 receptor engagement and β1-integrin clustering with downstream MAPK cell signaling

Eosinophils account for 1–3% of peripheral blood leukocytes and accumulate at sites of allergic inflammation, where they play a pathogenic role. Studies have shown that treatment with mepolizumab (an anti-IL-5 monoclonal antibody) is beneficial to patients with severe eosinophilic asthma, however, the mechanism of precisely how eosinophils mediate these pathogenic effects is uncertain. Eosinophils contain several cationic granule proteins, including Eosinophil Peroxidase (EPO). The main significance of this work is the discovery of EPO as a novel ligand for the HER2 receptor. Following HER2 activation, EPO induces activation of FAK and subsequent activation of β1-integrin, via inside-out signaling. This complex results in downstream activation of ERK1/2 and a sustained up regulation of both MUC4 and the HER2 receptor. These data identify a receptor for one of the eosinophil granule proteins and demonstrate a potential explanation of the proliferative effects of eosinophils.

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Eosinophil peroxidase (EPO) is confirmed as a ligand for the HER2 receptor.

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EPO activation of HER2 leads to activation of FAK, ERK and β1 integrin.

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EPO induces a sustained upregulation of MUC4 and HER2.

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Possible mechanism for the proliferative effects of eosinophils is uncovered.

The rat ErbB2 tyrosine kinase receptor produced in plants is immunogenic in mice and confers protective immunity against ErbB2(+) mammary cancer

The rat ErbB2 (rErbB2) protein is a 185-kDa glycoprotein belonging to the epidermal growth factor-related proteins (ErbB) of receptor tyrosine kinases. Overexpression and mutations of ErbB proteins lead to several malignancies including breast, lung, pancreatic, bladder and ovary carcinomas. ErbB2 is immunogenic and is an ideal candidate for cancer immunotherapy. We investigated the possibility of expressing the extracellular (EC) domain of rErbB2 (653 amino acids, aa) in Nicotiana benthamiana plants, testing the influence of the 23 aa transmembrane (TM) sequence on protein accumulation. Synthetic variants of the rErbB2 gene portion encoding the EC domain, optimized with a human codon usage and either linked to the full TM domain (rErbB2_TM, 676 aa), to a portion of it (rErbB2-pTM, 662 aa), or deprived of it (rErbB2_noTM, 653 aa) were cloned in the pEAQ-HT expression vector as 6X His tag fusions. All rErbB2 variants (72-74.5 kDa) were transiently expressed, but the TM was detrimental for rErbB2 EC accumulation. rERbB2_noTM was the most expressed protein; it was solubilized and purified with Nickel affinity resin. When crude soluble extracts expressing rErbB2_noTM were administered to BALB/c mice, specific rErbB2 immune responses were triggered. A potent antitumour activity was induced when vaccinated mice were challenged with syngeneic transplantable ErbB2(+) mammary carcinoma cells. To our knowledge, this is the first report of expression of rErbB2 in plants and of its efficacy in inducing a protective antitumour immune response, opening interesting perspectives for further immunological testing.

HER family receptor expression and prognosis in pancreatic cancer

BACKGROUND

HER family receptors play a key role in tumor progression in several malignancies, such as colorectal, lung or breast cancer. The aims of this study were to investigate expression of HER-1, HER-2 and HER-3 in pancreatic cancer (PC) samples and evaluate the association between HER-family receptor expression and patients' clinical outcomes.

METHODS

Tissue samples from 91 PC patients were subjected to immunohistochemical staining to assess the expression of HER-1, HER-2 and HER-3. Semiquantitative scores of zero (no staining or staining in less than 10% of cancer cells), 1+, 2+ or 3+ were assigned to each sample based on the intensity of staining for HER receptors. Scores of 2+ or 3+ were defined as positive staining.

RESULTS

HER-1 overexpression was observed in 41 out of 91 samples (45.1%), while HER-2 was not overexpressed in any of the analyzed samples. HER-3 was overexpressed in 37 samples (40.7%) and was found to be associated with advanced TNM stage. In particular, HER-3 was overexpressed in 12 out of 16 stage IV patients (75%) compared with only 33.3% of stage I-III patients (p = 0.02). Among 79 patients with available survival data, the 6 patients with strong HER-3 expression (score 3+) had a shorter survival compared with remaining patients (median overall survival 6.9 months vs. 12.3 months, respectively).

CONCLUSIONS

HER-1 and HER-3 were found to be expressed in a significant proportion of PC patients. Strong HER-3 expression represents an indicator of poor prognosis in PC patients, being associated with advanced stage and shorter survival.

Prognostıc value of increased HER2 expression in cancers of pancreas and biliary tree

Increased HER2 expression has a prognostic, and predictive value in many solid cancer types, predominantly in breast cancer. However the effects of HER2 on survival from cancers of pancreas, gall bladder, cholangiocellular, and ampullary region are not known. In this study, the effects of increased HER2 expression on these types of cancer have been analyzed. Immunohistochemical HER2 staining was performed in 31 (44.9 %) female, and 38 (55.1 %) male patients with a mean age of 65 ± 10 years, and various parameters, mostly survival rates of patients with pancreas (n = 30; 43.5 %), gall bladder (n = 17; 24.6 %), cholangiocellular (n = 12; 17.4 %), and ampullary region (n = 10; 14.5 %) carcinomas were evaluated. Strong (3 +) membranous staining for HER2 was observed in 2 patients with gall bladder cancers (11.76 % of all gall bladder cancers). In 2.90 % of all cases strong membranous staining (2+ or 3+) was observed. Weak (1+) membranous staining was noted in one (3.33 %) pancreatic, and one cholangiocellular (8.33 %) cancer patient, and in none of the ampullary region patient membranous staining for HER2 was observed. Since only scarce number of patients demonstrated membranous staining for HER2, survival analysis was not performed on these patients. Based on cytoplasmic HER2 staining scores, the patients were divided into weakly (0-3 pts; n = 17 patients; 24.66 %), moderate (4-5 pts; n = 22; 31.88 %), and strongly (6-7 pts; n = 30; 43.46 %) stained groups. Patients whose specimens demonstrated borderline statistical significant (p = 0.052) low staining for HER2 had higher survival rates when compared with other cases. Increased HER2 expression has no prognostic, and predictive value in cancers of pancreas, biliary tract, and ampulla vateri. If HER2 will be evaluated in these types of cancer, membranous, as well as cytoplasmic staining properties should be taken into account.

Active targeting using HER-2-affibody-conjugated nanoparticles enabled sensitive and specific imaging of orthotopic HER-2 positive ovarian tumors

Despite advances in cancer diagnosis and treatment, ovarian cancer remains one of the most fatal cancer types. The development of targeted nanoparticle imaging probes and therapeutics offers promising approaches for early detection and effective treatment of ovarian cancer. In this study, HER-2 targeted magnetic iron oxide nanoparticles (IONPs) are developed by conjugating a high affinity and small size HER-2 affibody that is labeled with a unique near infrared dye (NIR-830) to the nanoparticles. Using a clinically relevant orthotopic human ovarian tumor xenograft model, it is shown that HER-2 targeted IONPs are selectively delivered into both primary and disseminated ovarian tumors, enabling non-invasive optical and MR imaging of the tumors as small as 1 mm in the peritoneal cavity. It is determined that HER-2 targeted delivery of the IONPs is essential for specific and sensitive imaging of the HER-2 positive tumor since we are unable to detect the imaging signal in the tumors following systemic delivery of non-targeted IONPs into the mice bearing HER-2 positive SKOV3 tumors. Furthermore, imaging signals and the IONPs are not detected in HER-2 low expressing OVCAR3 tumors after systemic delivery of HER-2 targeted-IONPs. Since HER-2 is expressed in a high percentage of ovarian cancers, the HER-2 targeted dual imaging modality IONPs have potential for the development of novel targeted imaging and therapeutic nanoparticles for ovarian cancer detection, targeted drug delivery, and image-guided therapy and surgery.

CRABP-II is a highly sensitive and specific diagnostic molecular marker for pancreatic ductal adenocarcinoma in distinguishing from benign pancreatic conditions

CRABP-II, a retinoic acid binding protein, shuffles retinoic acid from cytoplasm into nucleus and forms a complex with nuclear retinoic acid receptor to facilitate transcriptional activities of retinoic acid. In this study, we studied the expression patterns of CRABP-II in pancreatic ductal adenocarcinoma (PDAC) compared with those in normal pancreas, chronic pancreatitis, and precancerous lesions. We showed no detectable expressions of CRABP-II in normal pancreatic parenchyma, normal ductal epithelium, and chronic pancreatitis. In contrast, the expression of CRABP-II was readily detected in all PDACs including metastatic PDACs. CRABP-II staining was also observed and progressively increased from pancreatic intraepithelial neoplasia 1 to 3. In addition, when fine needle aspiration specimens were evaluated from patients with PDAC, CRABP-II was positive in 55.6% cases if cytology diagnosis was "atypia," and in 87.5% cases, if "malignancy." Our study suggests that CRABP-II is highly and specifically expressed in PDAC and is more commonly expressed in high-grade precursor cancerous lesions than in low-grade lesions. Therefore, overexpression of CRABP-II is a late event of pancreatic carcinogenesis, and it could be used as a diagnostic marker to distinguish PDAC from other benign pancreatic conditions in both resection and cytology specimens.

In situ Protein Detection for Companion Diagnostics

The emergence of targeted therapies for cancer has created a need for the development of companion diagnostic tests. Assays developed in recent years are aimed at determining both the effectiveness and safety of specific drugs for a defined group of patients, thus, enabling the more efficient design of clinical trials and also supporting physicians when making treatment-related decisions. Immunohistochemistry (IHC) is a widely accepted method for protein expression analyses in human tissues. Immunohistochemical assays, used to localize and quantitate relative protein expression levels within a morphological context, are frequently used as companion diagnostics during clinical trials and also following drug approval. Herein, we describe established immunochemistry-based methods and their application in routine diagnostics. We also explore the possibility of using IHC to detect specific protein mutations in addition to DNA-based tests. Finally, we review alternative protein binders and proximity ligation assays and discuss their potential to facilitate the development of novel, targeted therapies against cancer.

Molecularly targeted therapies in metastatic pancreatic cancer: a systematic review

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

Prospective markers for early diagnosis and prognosis of sporadic pancreatic ductal adenocarcinoma

BACKGROUND AND AIM

Sporadic pancreatic ductal adenocarcinoma (PDA) is a highly lethal cancer. No proven screening strategies are available and frequent cross-sectional imaging studies (CT/MRI) are impractical even in patients thought to be at higher risk than the general population. Few PDA biomarkers have been studied prospectively for screening. Here, we prospectively evaluated the Adnab-9 monoclonal antibody in stool, pancreaticobiliary secretions, and tissue for screening and prognostic value in sporadic PDA. We also evaluated the prognostic value of characterized early biomarkers in pancreaticobiliary secretions.

METHODS

Adnab-9 diagnostic ability was tested in stool in 249 and 1,132 patients from China and the US, respectively. Immunohistochemistry was performed in 22 tissue samples with Adnab-9 antibody and anti-Defensin 5, a constituent of Paneth cells. Pancreatobiliary secretions were collected from 12 PDA patients and 9 controls. The enriched PCR method was performed to detect K-ras mutations. ELISA was performed with Adnab-9, anti-Her-2/neu, and monoclonal antibody D4 (anti-Reg I).

RESULTS

Adnab-9 alone was diagnostic and prognostic when measured in pancreatic secretions, feces, and tissues of PDA patients compared to controls (p < 0.05). Significantly, Adnab-9 fecal binding can precede the clinical diagnosis by 2.3 years, potentially allowing earlier clinical intervention. In pancreatic secretions, a combination of K-ras and Her-2/neu when appropriately standardized can be diagnostic in 75 % of PDA.

CONCLUSIONS

Our study suggests that Adnab-9 may be an effective marker for diagnosis and prognosis of PDA. Adnab-9 may be reflective of the presence of Paneth cells confirmed by Defensin-5 staining. These cells may modulate the biological activity of the cancer and confer a better prognosis.

What is recent in pancreatic cancer immunotherapy?

Pancreatic cancer (PC) represents an unresolved therapeutic challenge, due to the poor prognosis and the reduced response to currently available treatments. Pancreatic cancer is the most lethal type of digestive cancers, with a median survival of 4-6 months. Only a small proportion of PC patients is curative by surgical resection, whilst standard chemotherapy for patients in advanced disease generates only modest effects with considerable toxic damages. Thus, new therapeutic approaches, specially specific treatments such as immunotherapy, are needed. In this paper we analyze recent preclinical and clinical efforts towards immunotherapy of pancreatic cancer, including passive and active immunotherapy approaches, designed to target pancreatic-cancer-associated antigens and to elicit an antitumor response in vivo.

Potential targets for pancreatic cancer immunotherapeutics

Pancreatic adenocarcinoma is the fourth leading cause of cancer death with an overall 5-year survival of less than 5%. As there is ample evidence that pancreatic adenocarcinomas elicit antitumor immune responses, identification of pancreatic cancer-associated antigens has spurred the development of vaccination-based strategies for treatment. While promising results have been observed in animal tumor models, most clinical studies have found only limited success. As most trials were performed in patients with advanced pancreatic cancer, the contribution of immune suppressor mechanisms should be taken into account. In this article, we detail recent work in tumor antigen vaccination and the recently identified mechanisms of immune suppression in pancreatic cancer. We offer our perspective on how to increase the clinical efficacy of vaccines for pancreatic cancer.

Challenges of drug resistance in the management of pancreatic cancer

The current treatment of choice for metastatic pancreatic cancer involves single-agent gemcitabine or a combination of gemcitabine with capecitabine or erlotinib (a tyrosine kinase inhibitor). Only 25&#x2013;30% of patients respond to this treatment and patients who do respond initially ultimately exhibit disease progression. Median survival for pancreatic cancer patients has reached a plateau due to inherent and acquired resistance to these agents. Key molecular factors implicated in this resistance include: deficiencies in drug uptake, alteration of drug targets, activation of DNA repair pathways, resistance to apoptosis and the contribution of the tumor microenvironment. Moreover, for newer agents including tyrosine kinase inhibitors, overexpression of signaling proteins, mutations in kinase domains, activation of alternative pathways, mutations of genes downstream of the target and/or amplification of the target represent key challenges for treatment efficacy. Here we will review the contribution of known mechanisms and markers of resistance to key pancreatic cancer drug treatments.

HER2 overexpression correlates with survival after curative resection of pancreatic cancer

HER2 overexpression has been linked to clinical outcomes in several solid tumors, such as breast cancer. However, the correlation between HER2 overexpression and survival in pancreatic carcinoma remains unclear. The impact of HER2 overexpression on survival in pancreatic ductal cancer was examined. Immunohistochemical staining of 129 pancreatic cancers without hematogenous metastases or peritoneal dissemination treated by macroscopically curative resection were analyzed in association with survival data. To determine HER2 overexpression in this pancreatic cancer series, the polyclonal antibody included in HercepTest, which is used worldwide for clinical examination of HER2 overexpression in breast cancer, was used. Immunoreactivity was classified according to the scale presented in the HercepTest Scoring Guidelines. Twenty-two cases (17.1%) had a score of 0, 28 cases (21.7%) had of a score of 1+, 41 cases (31.8%) had a score of 2+, and 38 cases (29.4%) had a score of 3+. Therefore, HER2 overexpression (score 2+ or 3+) was observed in 79 cases (61.2%). Patients with HER2 overexpression tumors had significantly shorter survival times than those with HER2 normal expression (score 0 or 1+) tumors (median survival time, 14.7 vs 20.7 months, respectively; P = 0.0078 on the log-rank test). On multivariate survival analysis, HER2 overexpression remained an independent prognostic factor (hazard ratio, 1.806; P = 0.0258). A significant percentage of pancreatic cancers were demonstrated to have HER2 overexpression, and overexpression of this tyrosine kinase receptor proved to be an independent factor for a worse prognosis. These results should encourage further investigation of treatments using new molecular targeting agents against HER2 protein to improve the survival of pancreatic cancer patients.

HER-family gene amplification and expression in resected pancreatic cancer

AIMS

Despite surgical resection, pancreatic cancer carries a poor prognosis. In search for new molecular therapeutic targets, we investigated the expression of the HER-family and gene amplification of HER-2 in pancreatic adenocarcinomas of different stages.

METHODS

Tissue of 45 resected patients was analyzed for all HER-family 1-4 expression by immunohistochemistry and HER-2 gene amplification was assessed by multiplex ligation-dependent probe amplification and chromogenic in situ hybridization. The type of surgery, location, stage and grade of the tumor, as well as involvement of the resection margins were correlated with HER-expressions and univariate and multivariate survival analysis performed.

RESULTS

Normal pancreatic tissue lacked HER1-2 expression, but did show HER3-4 expression. In cancers, no membranous overexpression of HER-1 and HER-2 was seen nor gene amplification of HER-2 found. HER-3, HER-4 is physiologically expressed in the normal pancreas and loss of cytoplasmic HER-3 and HER-4 expression was seen in 33/45 (73%) and 8/45 (18%) of pancreatic cancers. Cytoplasmic HER-3 expression decreased from early to late stage (p=0.05). HER-4 expression was not associated with survival, stage or tumor grade. There were no statistically significant differences in HER1-4 expression between the papilla of Vater (n=13) and non-papilla cancers (n=32). Multivariate survival analysis showed only stage to be of independent prognostic value (p=0.015).

CONCLUSIONS

HER-1 and HER-2 are not overexpressed in pancreatic cancers. HER-3 and HER-4 are expressed in the normal pancreas but expression is lost in pancreatic cancer. HER-targeted therapy in pancreatic cancer is not supported by HER-expression of the tumor.

The status and role of ErbB receptors in human cancer

Changes in the expression of cellular receptors contribute to the progression of many types of solid tumors. In this review, we focus on the normal role of ErbB receptors as signal transducers and their contribution to carcinogenesis when there are abnormalities in ErbB signaling due to the overactivity of the receptors or the overexpression of ligands, which can lead to developmental defects and have been associated with many types of cancers.

Targeted therapies for pancreatic cancer

INTRODUCTION

Pancreatic cancer is a devastating malignancy and a leading cause of cancer mortality. Furthermore, early diagnosis represents a serious hurdle for clinicians, as symptoms are non-specific and usually manifest in advanced, treatment-resistant stages of the disease.

SOURCES OF DATA

Here, we review the rationale and progress of targeted therapies currently under investigation.

AREAS OF AGREEMENT

At present, chemoradiation regimes are administered palliatively, and produce only marginal survival benefits, underscoring a desperate need for more effective treatment modalities.

AREAS OF CONTROVERSY

Questions have been raised as to whether erlotinib, the only targeted therapy to attain a statistically significant increase in median survival, is cost-effective.

GROWING POINTS

The last decade of research has provided us with a wealth of information regarding the molecular nature of pancreatic cancer, leading to the identification of signalling pathways and their respective components which are critical for the maintenance of the malignant phenotype.

AREAS TIMELY FOR DEVELOPING RESEARCH

These proteins thus represent ideal targets for novel molecular therapies which embody an urgently needed novel treatment strategy.

Future strategies for targeted therapies and tailored patient management in pancreatic cancer

Pancreatic cancer represents the fourth leading cause of cancer-related mortality in the United States. The vast majority of patients are diagnosed at advanced stages of the disease, at which time gemcitabine-based chemotherapy is typically offered as the standard of care. However, as investigators have arrived at a greater understanding of pancreatic tumor biology, newer therapeutic agents that "target" specific pathways or molecules governing the growth, spread, and maintenance of tumor cells have gained considerable interest. Erlotinib, an orally bioavailable small molecule inhibitor of the epidermal growth factor receptor, is the first of these targeted compounds to be approved for use in combination with gemcitabine for patients with advanced pancreatic cancer. Other targeted agents, including monoclonal antibodies and small molecule inhibitors aimed at a variety of targets, also have been extensively evaluated, with limited success to date. A newer strategy worth pursuing involves tailoring an individual patient's therapy according to the molecular characteristics of both host and tumor, as has shown promise in other solid tumor types.

Differential c-erbB-1 and c-erbB-2 mRNA expression in cancer of the pancreas compared with cancer of the papilla of Vater

AIM: We examined quantitative mRNA expression of growth factor receptors (c-erbB-1, c-erbB-2) and the anti-apoptosis gene survivin known to be regulated in pancreatic adenocarcinomas and compared the expression pattern with that in carcinomas of the papilla of Vater.

METHODS: Quantitative real-time reverse transcriptase-PCR (QRT-PCR, Taqman^TM) was performed to analyze mRNA expression levels of c-erbB-1, c-erbB-2 and survivin in normal and corresponding tumor samples of 31 pancreatic adenocarcinomas and 8 cancers of the papilla of Vater.

RESULTS: The overall median mRNA expression of survivin was significantly increased in both adenocarcinoma of the pancreas (P<0.01) and papilla of Vater (P<0.008) compared with uninvolved normal control tissue. In pancreatic cancer, expression of c-erbB-1 was significantly decreased compared with the normal pancreatic tissue (P<0.03), whereas in the cancer of the papilla of Vater expression of c-erbB-2 was significantly downregulated (P<0.05) compared with the paired normal samples. Gene expression was not associated with tumor stage, differentiation or prognosis.

CONCLUSION: The common anti-apoptosis gene survivin is overexpressed both in the cancer of the papilla of Vater and pancreas. In contrast, the growth factor receptor genes c-erbB-1 and c-erbB-2 are differentially regulated in both tumor entities adding further evidence that pancreatic cancer is biologically different from the cancer of papilla of Vater.

Clinical significance of K-ras and c-erbB-2 mutations in pancreatic adenocarcinoma and chronic pancreatitis

BACKGROUND

The differentiation of chronic pancreatitis (CP) from pancreatic adenocarcinoma (PA) remains the great challenge for clinicians. The purpose of this study was to compare the prevalence of K-ras and c-erbB-2 mutations in PA and CP in order to evaluate their usefulness in differential diagnosis of those diseases.

METHODS

The study included 49 patients who underwent Whipple resection or distal pancreatectomy for pancreatic adenocarcinoma (26 subjects) or chronic pancreatitis (23 subjects). DNA from pancreatic tissue was analyzed for K-ras codon 12 and c-erbB-2 mutations with PCR amplifications.

RESULTS

The K-ras gene mutation has been shown in 20 (76.9%) PA cases and in 8 (34.8%) CP cases (p<0.01). Prevalence of c-erbB-2 amplification in patients with PA was 17 (65.3%), which was not different from CP, 16 (56.5%) (p=0.58). There was a significant correlation between K-ras mutation and lymph node metastases (p=0.025) as well as between K-ras mutation and G3 tumor differentiation (p=0.037). Overall median survival in patients with PA was 9.5 mo. There was no relationship between presence of K-ras (p=0.58) or c-erbB-2 (p=0.17) mutation and survival time in PA patients.

CONCLUSION

Those results may indicate that both K-ras and c-erbB-2 play a role in pancreatic carcinogenesis, however only K-ras may provide an additional tool in differential diagnosis of CP and PC.

Clinical significance of K-ras and c-erbB-2 mutations in pancreatic adenocarcinoma and chronic pancreatitis

BACKGROUND

The differentiation of chronic pancreatitis (CP) from pancreatic adenocarcinoma (PA) remains the great challenge for clinicians. The purpose of this study was to compare the prevalence of K-ras and c-erbB-2 mutations in PA and CP in order to evaluate their usefulness in differential diagnosis of those diseases.

METHODS

The study included 49 patients who underwent Whipple resection or distal pancreatectomy for pancreatic adenocarcinoma (26 subjects) or chronic pancreatitis (23 subjects). DNA from pancreatic tissue was analyzed for K-ras codon 12 and c-erbB-2 mutations with PCR amplifications.

RESULTS

The K-ras gene mutation has been shown in 20 (76.9%) PA cases and in 8 (34.8%) CP cases (p<0.01). Prevalence of c-erbB-2 amplification in patients with PA was 17 (65.3%), which was not different from CP, 16 (56.5%) (p=0.58). There was a significant correlation between K-ras mutation and lymph node metastases (p=0.025) as well as between K-ras mutation and G3 tumor differentiation (p=0.037). Overall median survival in patients with PA was 9.5 mo. There was no relationship between presence of K-ras (p=0.58) or c-erbB-2 (p=0.17) mutation and survival time in PA patients.

CONCLUSION

Those results may indicate that both K-ras and c-erbB-2 play a role in pancreatic carcinogenesis, however only K-ras may provide an additional tool in differential diagnosis of CP and PC.

Herceptin Down-Regulates HER-2/neuand Vascular Endothelial Growth Factor Expression and Enhances Taxol-Induced Cytotoxicity of Human Ewing's Sarcoma CellsIn vitroandIn vivo

We have previously shown that high levels of HER-2/neu protein were overexpressed in human Ewing's sarcoma cells (TC71, SK-ES1) relative to normal human osteoblasts. The purpose of this study was to determine whether herceptin alone or in combination with chemotherapeutic agents could inhibit the growth of Ewing's sarcoma in vitro and in vivo. Western blot analysis showed that the protein levels of HER-2/neu were decreased following herceptin treatment. Cell growth was also inhibited by herceptin in a dose-dependent manner with an IC(50) of 4 mg/mL in TC71 and SK-ES1 cell line, whereas human immunoglobin had no effect. Northern blot and ELISA showed the RNA expression and protein levels of vascular endothelial growth factor were also inhibited by herceptin treatment with no alteration in HIF-1alpha protein and topoisomerase IIalpha expression. Furthermore, Ewing's sarcoma tumor growth was significantly delayed by 100 mg/kg herceptin treatment in our Ewing's sarcoma xenograft mouse model. Combining taxol with herceptin resulted in additive cytotoxicity, whereas herceptin-etoposide, doxorubicin, and 9-nitrocamptothecin combinations did not. Taxol-herceptin enhanced growth inhibition in TC71 cells in vitro compared with either agent alone. Ewing's sarcoma growth was also delayed in vivo and mean tumor size was significantly lower in mice treated with herceptin plus taxol than in those receiving taxol or herceptin alone. These data suggest that herceptin in combination with taxol may be a therapeutic option in the treatment of Ewing's sarcoma.

Inhibition ofMUC4Expression Suppresses Pancreatic Tumor Cell Growth and Metastasis

The MUC4 mucin is a high molecular weight membrane-bound glycoprotein. It is aberrantly expressed in pancreatic tumors and tumor cell lines with no detectable expression in the normal pancreas. A progressive increase of MUC4 expression has also been observed in pancreatic intraepithelial neoplasia, suggesting its association with disease development. Here, we investigated the consequences of silencing MUC4 expression in an aggressive and highly metastatic pancreatic tumor cell line CD18/HPAF that expresses high levels of MUC4. The expression of MUC4 was down-regulated by the stable integration of a plasmid-construct expressing antisense-MUC4 RNA. A decrease in MUC4 expression, confirmed by Western blot and immunofluorescence analyses, resulted in diminished growth and clonogenic ability of antisense-MUC4-transfected (EIAS19) cells compared with parental, empty vector (ZEO) and sense transfected (ES6) control cells. In addition, EIAS19 cells displayed a significant decrease in tumor growth and metastatic properties when transplanted orthotopically into the immunodeficient mice. In vitro biological assays for motility, adhesion, and aggregation demonstrated a 3-fold decrease in motility of EIAS19 cells compared with control cells, whereas these cells adhered more and showed an increase in cellular aggregation. Interestingly, MUC4 down-regulation also correlated with the reduced expression of its putative interacting partner, HER2/neu, in antisense-MUC4-transfected cells. In conclusion, the present work demonstrates, for the first time, a direct association of the MUC4 mucin with the metastatic pancreatic cancer phenotype and provides experimental evidence for a functional role of MUC4 in altered growth and behavioral properties of the tumor cell.

HER2 is frequently over-expressed in ovarian clear cell adenocarcinoma: possible novel treatment modality using recombinant monoclonal antibody against HER2, trastuzumab

Ovarian clear cell adenocarcinoma (CCA) is generally chemo-resistant. Recently the poor prognosis and resistance to chemotherapeutic agents of HER2/neu over-expressing tumors have become clear. Thus, we investigated the expression level of HER2 in surgically resected CCA and ovarian serous adenocarcinoma, endometrioid adenocarcinoma, and mucinous adenocarcinoma specimens, as well as CCA cell lines, by an immunohistochemical method. HER2 was over-expressed in 42.9% of CCA (P=0.026, vs. ovarian serous adenocarcinoma), 20.8% of ovarian serous adenocarcinoma, 23.1% of ovarian endometrioid adenocarcinoma, and 30.0% of mucinous adenocarcinoma specimens. Three CCA cell lines, RMG-1, HAC-II and KK were also positively stained for HER2. A flow-cytometric study of HER2 revealed 7.2-, 6.4- and 4.5-fold greater expression of HER2 than that of normal mammary gland, respectively. Trastuzumab, a humanized recombinant monoclonal antibody against HER2 significantly and dose-dependently reduced the growth of CCA cell lines in vitro. The extent of the inhibitory effect of trastuzumab was dependent on the expression level of HER2. Trastuzumab also dose-dependently inhibited the growth of xenografted RMG-1 tumor. The survival period of trastuzumab-treated mice was longer than that of the control group. From these findings, trastuzumab appears to be a candidate as a treatment modality for HER2 over-expressing ovarian CCA.

Targeting HER2 in other tumor types

The human epidermal growth factor receptor-2 (HER2) is overexpressed/amplified in a range of tumor types including breast, ovarian, bladder, salivary gland, endometrial, pancreatic and non-small-cell lung cancer (NSCLC). HER2 is implicated in disease initiation and progression, associated with poor prognosis, and may also predict the response to chemotherapy and hormonal therapy. Anti-HER2 monoclonal antibodies (MAbs) have been designed to specifically antagonize the function of the HER2 receptor in HER2-positive tumors. Clinical phase II and III trials have demonstrated the efficacy of the humanized anti-HER2 MAb, trastuzumab (Herceptin), both as a single agent and in combination with chemotherapy in HER2-positive, metastatic breast cancer patients. However, the prevalence of HER2 overexpression/amplification in various tumor types raises the possibility of using anti-HER2 MAbs to antagonize the abnormal function of overexpressed HER2 receptors in HER2-positive tumors other than breast. Preliminary in vitro studies indicate that anti-HER2 MAbs suppress the proliferation of ovarian, gastric and NSCLC cell lines that overexpress the HER2 receptor. These results indicate that anti-HER2 MAbs may have important therapeutic significance in patients presenting with these or other human carcinomas. Clinical trials are either planned or underway to assess the therapeutic role of trastuzumab in NSCLC, bladder and ovarian cancer.

HER2 overexpression in various tumor types, focussing on its relationship to the development of invasive breast cancer

To date, poor standardization in HER2 status evaluation has precluded reliable comparison of overexpression rates in different tumors. However, standardized methodologies have been introduced recently for these analyses, and have identified frequencies of 51%, 44%, 26% and 25% in Wilm's tumor, bladder, pancreatic and breast carcinoma, respectively. Other tumors tested had frequencies below 20%. The frequency was greater than that predicted by gene amplification data in some tumor types, which may indicate overexpression due to gene deregulation, rather than gene amplification. Analysis of a large retrospective series of breast carcinomas demonstrated an association between HER2 positivity and a number of other prognostic markers. Together, these variables identify a subset of tumors with poor prognosis and early relapse post-surgery. HER2 expression is relatively stable, with 95% concordance between the HER2 status of primary and metastatic lesions. However, contralateral tumors are unrestricted with regard to HER2 status. Preliminary data indicate that the HER2 status of a hormone receptor-positive tumor may fluctuate according to the menstrual cycle. It is anticipated that the emerging wealth of standardized data for HER2 status will help to elucidate the role of HER2 in tumor progression.

Comparative phenotypic studies of duct epithelial cell lines derived from normal human pancreas and pancreatic carcinoma

We have investigated the mRNA/protein expression of several tyrosine kinase receptors, growth factors, and p16INK4A cyclin inhibitor in cell lines derived from normal human pancreatic duct epithelium (HPDE) and compared them with those of five pancreatic ductal carcinoma cell lines. Cultured HPDE cells express low levels of epidermal growth factor receptor (EGFR), erbB2, transforming growth factor (TGF)-alpha, Met/hepatocyte growth factor receptor (HGFR), vascular endothelial growth factor (VEGF), and keratinocyte growth factor (KGF). They also expressed high levels of amphiregulin but did not express EGF and cripto. The expression levels were similar in primary normal HPDE cells and those expressing transfected E6E7 genes of human papilloma virus-16, but their immortalization appeared to enhance the expression of EGFR and Met/HGFR. In comparison, pancreatic carcinoma cell lines commonly demonstrated overexpression of EGFR, erbB2, TGF-alpha, Met/HGFR, VEGF, and KGF, but they consistently showed marked down-regulation of amphiregulin mRNA expression. In contrast to all carcinoma cell lines that showed deletions of the p16 gene, HPDE cells consistently demonstrated normal p16 genotype and its mRNA expression. This is the first report that compares the phenotypic expression of cultured pancreatic ductal carcinoma cells with epithelial cell lines derived from normal human pancreatic ducts. The findings confirm that malignant transformation of human pancreatic duct cells commonly results in a deregulation of expression of various growth factors and receptors.

The use of molecular technology in the differentiation of pancreatic cancer and chronic pancreatitis

CONCLUSION

It is concluded that currently there are limitations in the use of some of the proposed tests, whereas in the future, further progress in our understanding of the molecular biology of pancreatic disease and the development and application of existing techniques should have a greater impact on clinical practice.

BACKGROUND

Fifteen to 20% of patients with pancreatic cancer present with a resectable mass in the head of the pancreas, but there is a subgroup of patients for whom it is difficult to reach the correct diagnosis.

METHOD

This article addresses how molecular technology can be used to aid in the diagnosis of this group of patients. The clinical and scientific literature is reviewed by accessing papers through the Medline database.

RESULTS

This article reviews the limitations of conventional imaging techniques and the limitations of fine needle aspiration cytology and cytological examination of pancreatic duct secretions. The molecular biology of both pancreatic cancer and chronic pancreatitis is then reviewed with emphasis on the common molecular defects seen in these diseases. The current use of molecular techniques in the examination of cytological and histological specimens, stool, blood, and pancreatic duct secretions and how this helps discriminate between benign and malignant lesions of the pancreas is addressed. Finally, the use of novel serum screening tests in groups at high risk of pancreatic cancer is discussed.