Ductal cancers of the pancreas frequently express markers of gastrointestinal epithelial cells

The preclinical discovery and development of zolbetuximab for the treatment of gastric cancer

INTRODUCTION

Gastric cancer remains a formidable challenge in oncology with high mortality rates and few advancements in treatment. Claudin-18.2 (CLDN18.2) is a tight junction protein primarily expressed in the stomach and is frequently overexpressed in certain subsets of gastric cancers. Targeting CLDN18.2 with monoclonal antibodies, such as zolbetuximab (IMAB362), has shown promising efficacy results in combination with chemotherapy.

AREAS COVERED

The molecular cell biology of CLDN18.2 is discussed along with studies demonstrating the utility of CLDN18.2 expression as a biomarker and therapeutic target. Important clinical studies are reviewed, including Phase III trials, SPOTLIGHT and GLOW, which demonstrate the efficacy of zolbetuximab in combination with chemotherapy in patients with CLDN18.2-positive advanced gastric cancer.

EXPERT OPINION

CLDN18.2 is involved in gastric differentiation through maintenance of epithelial barrier function and coordination of signaling pathways, and its expression in gastric cancers reflects a 'gastric differentiation' program. Targeting Claudin-18.2 represents the first gastric cancer specific 'targeted' treatment. Further studies are needed to determine its role within current gastric cancer treatment sequencing, including HER2-targeted therapies and immunotherapies. Management strategies will also be needed to better mitigate zolbetuximab-related treatment side effects, including gastrointestinal (GI) toxicities.

A narrative review on rare types of pancreatic cancer: should they be treated as pancreatic ductal adenocarcinomas?

Pancreatic cancer is one of the deadliest malignancies in humans and it is expected to play a bigger part in cancer burden in the years to come. Pancreatic ductal adenocarcinoma (PDAC) represents 85% of all primary pancreatic malignancies. Recently, much attention has been given to PDAC, with significant advances in the understanding of the mechanisms underpinning disease initiation and progression, along with noticeable improvements in overall survival in both localized and metastatic settings. However, given their rarity, rare histological subtypes of pancreatic cancer have been underappreciated and are frequently treated as PDAC, even though they might present non-overlapping molecular alterations and clinical behavior. While some of these rare histological subtypes are true variants of PDAC that should be treated likewise, others represent separate clinicopathological entities, warranting a different therapeutic approach. In this review, we highlight clinical, pathological, and molecular aspects of rare histological types of pancreatic cancer, along with the currently available data to guide treatment decisions.

De novo expression of gastrokines in pancreatic precursor lesions impede the development of pancreatic cancer

Molecular events occurring in stepwise progression from pre-malignant lesions (pancreatic intraepithelial neoplasia; PanIN) to the development of pancreatic ductal adenocarcinoma (PDAC) are poorly understood. Thus, characterization of early PanIN lesions may reveal markers that can help in diagnosing PDAC at an early stage and allow understanding the pathology of the disease. We performed the molecular and histological assessment of patient-derived PanINs, tumor tissues and pancreas from mouse models with PDAC (KC mice that harbor K-RAS mutation in pancreatic tissue), where we noted marked upregulation of gastrokine (GKN) proteins. To further understand the role of gastrokine proteins in PDAC development, GKN-deficient KC mice were developed by intercrossing gastrokine-deficient mice with KC mice. Panc-02 (pancreatic cancer cells of mouse origin) were genetically modified to express GKN1 for further in vitro and in vivo analysis. Our results show that gastrokine proteins were absent in healthy pancreas and invasive cancer, while its expression was prominent in low-grade PanINs. We could detect these proteins in pancreatic juice and serum of KC mice. Furthermore, accelerated PanIN and tumor development were noted in gastrokine deficient KC mice. Loss of gastrokine 1 protein delayed apoptosis during carcinogenesis leading to the development of desmoplastic stroma while loss of gastrokine 2 increased the proliferation rate in precursor lesions. In summary, we identified gastrokine proteins in early pancreatic precursor lesions, where gastrokine proteins delay pancreatic carcinogenesis.

Unusual Case of Pancreatic Adenocarcinoma with Bladder Metastasis

Background: The pancreas can be the site of neoplasms of several histogenetic origins; in most cases, tumors derive from the exocrine component, and ductal adenocarcinoma certainly prevails over the others. This tumor displays remarkably aggressive behavior, and it is often diagnosed at a late stage of disease. Case presentation: We discuss the rare case of a 76-year-old male with locally advanced pancreatic head adenocarcinoma who developed uncommon metastatic disease. The bladder constitutes a very rare site of metastases, mostly deriving from melanoma, gastric, lung and breast cancers. The bladder's secondary involvement in pancreatic malignancies represents an extremely unusual occurrence, and there are very few cases described in the literature to date. Conclusions: The finding of pancreatic adenocarcinoma metastases leads to a poor prognosis, and patients who are diagnosed at this stage constitute 53% of cases, with a 5-year survival of 3%. Although rare, therefore, the diagnostic hypothesis of pancreatic ductal adenocarcinoma (DAC) metastases to the bladder must, in some cases, be considered, especially if accompanied by a clinical picture that may suggest it.

Cathepsin E expression and activity: Role in the detection and treatment of pancreatic cancer

Cathepsin E (CTSE) is an intracellular, hydrolytic aspartic protease found to be expressed in cells of the immune and gastrointestinal systems, lymphoid tissues, erythrocytes, and cancer cells. The precise functions are not fully understood; however, various studies have investigated its numerous cell-type specific roles. CTSE expression has been shown to be a potential early biomarker for pancreatic ductal adenocarcinoma (PDAC). PDAC patients have low survival rates mostly due to the lack of early detection methods. CTSE-specific activity probes have been developed and tested to assist in tumor imaging and functional studies investigating the role of CTSE expression in PDAC tumors. Furthermore, a CTSE protease-specific, photodynamic therapy pro-drug was developed to explore its potential use to treat tumors that express CTSE. Since CTSE is expressed in pancreatic diseases that are risk factors for PDAC, such as pancreatic cysts and chronic pancreatitis, learning about its function in these disease types could assist in early PDAC detection and in understanding the biology of PDAC progression. Overall, CTSE expression and activity shows potential to detect PDAC and other pancreatic diseases. Further research is needed to fully understand its functions and potential translational applicability.

Helicobacter pylori infection, atrophic gastritis, and risk of pancreatic cancer: A population-based cohort study in a large Japanese population: the JPHC Study

Helicobacter pylori (H. pylori), an established risk factor for gastric cancer, is suggested to also play a role in the development of pancreatic cancer; however, the association remains inconclusive. We examined this association among Japanese men and women. H. pylori and atrophic gastritis (AG) status were determined serologically, using blood sample collected during health checkups. A total of 20,116 subjects enrolled in the Japan Public Health Center-based Prospective Study Cohort II with available data on H. pylori seropositivity (anti-H. pylori) and AG were followed until the end of 2010. Cox proportional hazards models were used to calculate the hazard ratios (HR) and 95% confidence intervals (CI), using the information from the baseline survey. During 320,470 person-years of follow-up, 119 cases of pancreatic cancer were identified. No statically significant increase or decrease in pancreatic cancer risk was observed for H. pylori and AG status, independently or in combination. In a multivariable-adjusted model, we observed a non-significant decrease in the risk among those who had AG but were anti-H. pylori seronegative (HR 0.57, 95% CI 0.31–1.03). In a stratified analysis, we observed a statistically significant increased risk of pancreatic cancer for AG+ (HR 3.64, 95% CI 1.37–9.66), and AG+/anti-H. pylori− or AG+/anti-H. pylori+ (HR 5.21, 95% CI 1.14–23.87) among current smokers. Non-smokers in all categories of AG and anti-H. pylori showed a non-statistical decrease in the risk. There was no statistically significant interaction between H. pylori infection, AG status, and smoking status. Our findings suggest H. pylori seropositivity and AG, individually or in combination, are not associated with the risk of pancreatic cancer in a general Japanese population. Among current smokers, pancreatic cancer risk increased with AG, regardless of H. pylori infection status.

Pepsinogen C Expression in Tumors of Extragastric Origin

We have examined by immunohistochemistry the ability of human carcinomas of various origin to produce pepsinogen C, an aspartyl proteinase mainly involved in the digestion of proteins in the stomach and recently found to be associated with breast carcinomas. Of the 268 tumors analyzed 80 (29.8%) showed positive staining for pepsinogen C. These positive tumors included 12 gastric (38.7% of the 31 examined cases), nine pancreatic (42.8%), two renal (20%), 12 prostatic (40%), three bladder (27.3%), 14 endometrial (29.7%) and 18 ovarian (40%) carcinomas. We also detected 10 melanomas (50%) that were positive for pepsinogen C. By contrast, immunohistochemical staining for the proteinase was not detected in colorectal, cervical, lung and basal cell skin carcinomas. These results demonstrate that pepsinogen C, a proteolytic enzyme of highly restricted expression in human tissues, can also be expressed by a wide variety of human carcinomas. In addition, and similar to pepsinogen C expression in breast carcinomas, the production of this enzyme by different human tumors might be related to putative hormonal alterations associated with the development and progression of these tumors.

Expression and Clinical Significance of Pepsinogen C in Resectable Pancreatic Cancer

Pepsinogen C is an aspartyl-proteinase usually involved in the digestion of proteins in the stomach, and an androgen- inducible protein in breast cancer cells. In this study we evaluated its expression and clinical significance in patients with resectable pancreatic cancer. Pepsinogen C expression was examined by immunohistochemical methods in a series of 73 pancreatic carcinomas. The prognostic value of pepsinogen C was retrospectively evaluated by multivariate analysis. A total of 21 (28.8%) pancreatic carcinomas stained positively for pepsinogen C. The percentage of pepsinogen C-positive tumors was significantly higher in well-differentiated tumors (38.3%) than in moderately differentiated (15.8%) and poorly differentiated (0%) tumors (p<0.05). In addition, statistical analysis revealed that pepsinogen C expression was associated with clinical outcome. Thus, patients with pepsinogen C-negative tumors have a poorer overall survival than those with pepsinogen C-positive tumors. Our results led us to consider that the expression of pepsinogen C may represent a useful biological marker in pancreatic cancer. Expression of this protein may be a marker of gastric-type differentiation of the tumors and it might also reflect the existence of a complete hormone receptor pathway in a subset of pancreatic carcinomas.

SPan-1 and Exocrine Pancreatic Carcinoma. The Clinical Role of a New Tumor Marker

AIMS OF THE STUDY

Considerable progress has been made in imaging techniques over the past few years, yet this has not resulted in the ability to reach an earlier diagnosis of exocrine pancreatic cancer. The search for a noninvasive diagnostic tool capable of early diagnosis has led to the development of a series of serum tumor markers. This article discusses the clinical evaluation of SPan-1 and its comparison with established markers such as CA 19.9, CEA, TPA and CA 242.

METHODS

The markers were measured in preoperative serum samples collected from 46 patients who had undergone surgery for ductal carcinoma of the pancreas, 20 patients with chronic pancreatitis, and 23 patients with other digestive neoplasms.

RESULTS

The sensitivity, specificity and diagnostic accuracy for pancreatic cancer were as follows: [table: see text]

CONCLUSIONS

The antigenic determinant SPan-1, recognized by monoclonal antibodies, is elevated in sera of patients with exocrine pancreatic cancer. SPan-1 may be considered as an additional useful and reliable serum marker for the detection of this neoplasm, but it does not significantly improve the diagnostic accuracy obtained with CA 19.9.

Helicobacter pylori infection, atrophic gastritis, and pancreatic cancer risk: A meta-analysis of prospective epidemiologic studies

BACKGROUND

To investigate the associations of Helicobacter pylori (Hp) infection and atrophic gastritis (AG) with pancreatic cancer risk.

METHODS

A literature search in PubMed was performed up to July 2017. Only prospective cohort and nested case-control studies enrolling cancer-free participants were eligible. Incident pancreatic cancer cases were ascertained during the follow-up. The risks of pancreatic cancer were compared between persons infected and noninfected with Hp, or between those with and without AG status at baseline. Odds ratios (ORs) or hazard ratios were combined. Subgroup and sensitivity analyses were performed, and publication bias was estimated.

RESULTS

Three cohort studies and 6 nested case-control studies, including 65,155 observations, were analyzed. The meta-analyses did not confirm the association between pancreatic cancer risk and Hp infection (OR = 1.09, 95% confidence interval [CI] = 0.81-1.47) or AG status (OR = 1.18, 95% CI = 0.80-1.72). However, particular subpopulations potentially had increased risks of pancreatic cancer. Cytotoxin-associated gene A (CagA)-negative strains of Hp might be a causative factor of pancreatic cancer (OR = 1.30, 95% CI = 1.05-1.62), but a sensitivity analysis by leave-one-out method did not fully warrant it (OR = 1.20, 95% CI = 0.93-1.56). In 1 nested case-control study, AG at stomach corpus in Hp-negative subpopulation might have increased risk of pancreatic cancer, but with a poor test power = 0.56. Publication biases were nonsignificant in the present meta-analysis.

CONCLUSION

Based on current prospective epidemiologic studies, the linkage of pancreatic cancer to Hp infection or AG status was not warranted on the whole. Nevertheless, prospective studies only focusing on those specific subpopulations are further required to obtain better power.

Pancreatic Ductal Adenocarcinoma and Its Variants

Pancreatic cancer represents the seventh leading cause of cancer death in the world, responsible for more than 300,000 deaths per year. The most common tumor type among pancreatic cancers is pancreatic ductal adenocarcinoma, an infiltrating neoplasm with glandular differentiation that is derived from pancreatic ductal tree. Here we present and discuss the most important macroscopic, microscopic, and immunohistochemical characteristics of this tumor, highlighting its key diagnostic features. Furthermore, we present the classic features of the most common variants of pancreatic ductal adenocarcinoma. Last, we summarize the prognostic landscape of this highly malignant tumor and its variants.

High Expression of Cathepsin E is Associated with the Severity of Airflow Limitation in Patients with COPD

BACKGROUND

It was reported that Cathepsin E (Cat E) plays a critical role in antigen processing and in the development of pulmonary emphysema. The aim of this study was to investigate the role of Cat E and airflow limitation in the pathogenesis of COPD.

METHODS

Sixty-five patients with COPD, 20 smoking control subjects without COPD and 15 non-smoking healthy control subjects were enrolled. Cat E and EIC (Elastase inhibitory capacity) expressions were measured by ELISA in sputum and serum samples and compared according to different subgroups.

RESULTS

Cat E concentrations were significantly higher in patients with COPD than smoking control and non-smoking control subjects (P < 0.01). The levels of CatE were inversely correlated with FEV1% predicted in COPD patients (r = -0.95, P < 0.01). The levels of EIC were inversely positively correlated with FEV1% predicted in COPD patients (r = 0.926, P < 0.01). Levels of Cat E were also inversely correlated with the levels of EIC (r = -0.922, P < 0.01).

CONCLUSIONS

Cat E contributes to the severity of airflow limitation during progression of COPD.

Reappraisal of the Immunophenotype of Pancreatic Intraductal Papillary Mucinous Neoplasms (IPMNs)-Gastric Pyloric and Small Intestinal Immunophenotype Expression in Gastric and Intestinal Type IPMNs-

Pancreatic intraductal papillary mucinous neoplasms (IPMNs) are mucin-producing neoplasms of the main and/or branch pancreatic ducts. To assess differences between various IPMN subtypes, immunohistochemical markers of gastric surface mucous cells (MUC5AC), gastric gland mucous cells (MUC6 and GlcNAcα1→4Galβ→R), gastric pyloric and duodenal epithelial cells (PDX1), intestinal cells (MUC2 and CDX2), small intestinal cells (CPS1) and large intestinal cells (SATB2) were evaluated in 33 surgically treated IPMNs. MUC2 expression classified IPMNs into gastric (n=17), intestinal (n=8) and mixed gastric and intestinal type (collision=7, composite=1). No differences in age or sex were observed among these types. MUC5AC and PDX1 were expressed in all IPMNs. MUC6 expression was higher in gastric and mixed types than in intestinal type. GlcNAcα1→4Galβ→R was detected in gastric and mixed type, but not in intestinal type. MUC2 and CDX2 expression were higher in intestinal type than gastric and mixed type. CPS1 expression was higher in intestinal type than gastric type. SATB2 was not observed in any IPMNs. Frequent abrupt transition between the two IPMN types in mixed-type IPMNs was observed. Gastric pyloric and small intestinal differentiation are characteristic of gastric and intestinal type IPMN, respectively, and these two IPMN types may have distinct pathogenesis.

Targeting cathepsin E in pancreatic cancer by a small molecule allows in vivo detection

When resectable, invasive pancreatic ductal adenocarcinoma (PDAC) is most commonly treated with surgery and radiochemotherapy. Given the intricate local anatomy and locoregional mode of dissemination, achieving clean surgical margins can be a significant challenge. On the basis of observations that cathepsin E (CTSE) is overexpressed in PDAC and that an United States Food and Drug Administration (FDA)-approved protease inhibitor has high affinity for CTSE, we have developed a CTSE optical imaging agent [ritonavir tetramethyl-BODIPY (RIT-TMB)] for potential intraoperative use. We show nanomolar affinity [half maximal inhibitory concentration (IC50) of 39.9 ± 1.2 nM] against CTSE of the RIT-TMB in biochemical assays and intracellular accumulation and target-to-background ratios that allow specific delineation of individual cancer cells. This approach should be useful for more refined surgical staging, planning, and resection with curative intent.

Risk factors for pancreatic ductal adenocarcinoma specifically stimulate pancreatic duct glands in mice

Diabetes mellitus type 2 and chronic pancreatitis are regarded as risk factors for pancreatic cancer. Pancreatic duct glands (PDGs) were recently described as a new compartment of the major duct in humans and mice. To evaluate the influence of diabetes and chronic pancreatitis on PDGs, cerulein was injected i.p., repetitively over 10 weeks, in mice exhibiting obesity and a type 2 diabetes-like syndrome (B6.V-Lep(ob/ob)) and in lean littermates. By using 5-bromo-2'-deoxyuridine (BrdU), a label-retaining cell population was characterized in PDGs. Cerulein administration led to more BrdU(+) cells in PDGs of obese mice compared with lean mice. The observed increase was specific to PDGs, because BrdU incorporation in cells of the pancreatic duct was not increased. In addition, the expression of distinct tumor markers in PDGs was characterized by Muc5ac, S100P, regenerating islet-derived 3β, 14-3-3 σ, and prostate stem cell antigen immunochemistry. Type 2 diabetes-like syndrome, accompanied by chronic pancreatitis, enhanced nuclear localization of S100P. Both risk factors for pancreatic cancer also induced the production of Muc5ac and the nuclear localization of S100P [corrected]. These results demonstrate that diabetes and chronic pancreatitis jointly enhance BrdU incorporation and production of pancreatic cancer-specific proteins in PDGs. The observed alterations suggest that pancreatic tumors might originate from the newly discovered histomorphological structures, called PDGs, which could represent a target for future anticancer therapies.

Diverse monoclonal antibodies against the CA 19-9 antigen show variation in binding specificity with consequences for clinical interpretation

The CA 19-9 antigen is currently the best individual marker for the detection of pancreatic cancer. In order to optimize the CA 19-9 assay and to develop approaches to further improve cancer detection, it is important to understand the specificity differences between CA 19-9 antibodies and the consequential affect on biomarker performance. Antibody arrays enabled multiplexed comparisons between five different CA 19-9 antibodies used in the analysis of plasma samples from pancreatic cancer patients and controls. Major differences were observed between antibodies in their detection of particular patient samples. Glycan array analysis revealed that certain antibodies were highly specific for the canonical CA 19-9 epitope, sialyl-Lewis A, while others bound sialyl-Lewis A in addition to a related structure called sialyl-Lewis C and modification with Nue5Gc. In a much larger patient cohort, we confirmed the binding of sialyl-Lewis C glycan by one of the antibodies and showed that the broader specificity led to the detection of an increased number of cancer patients without increasing detection of pancreatitis patient samples. This work demonstrates that variation between antibody specificity for cancer-associated glycans can have significant implications for biomarker performance and highlights the value of characterizing and detecting the range of glycan structures that are elevated in cancer.

Expression of gastrin-releasing peptide is increased by prolonged stretch of human myometrium, and antagonists of its receptor inhibit contractility

Increased uterine stretch appears to increase the risk of preterm labour, but the mechanism is unknown. The aim of this study was to identify factors that mediate the effect of stretch on human myometrium.Myometrial explants, prepared from biopsies obtained at elective caesarean delivery, were either studied acutely, or were maintained in prolonged culture (up to 65 h) under tension with either a 0.6 g or a 2.4 g mass, and compared using in vitro contractility, whole genome array, and qRT-PCR. Tissue held at tonic stretch with the 2.4 g mass for either 24 or 65 h showed increased potassium chloride (KCl)-induced and oxytocin-induced contractility compared with that held with the 0.6 g mass. Gene array identified 62 differentially expressed transcripts after 65 h exposure to increased stretch. Two probes for gastrin-releasing peptide (GRP), a known stimulatory agonist of smooth muscle, were among the top five up-regulated by stretch (3.4-fold and 2.0-fold). Up-regulation of GRP mRNA by stretch was confirmed in a separate series of 10 samples using quantitative RT-PCR (qRT-PCR) (2.8-fold, P =0.01). GRP stimulated contractions acutely when added to freshly obtained myometrial strips in 2 out of 9 cases, but Western blot demonstrated expression of the GRP receptor in 9 out of a further 9 cases. Prolonged incubation of stretched explants in the GRP antagonists PD-176252 or RC-3095 (65 and 24 h, respectively) significantly reduced KCl- and oxytocin-induced contractility.Tonic stretch of human myometrium increases contractility and stimulates the expression of a known smooth muscle stimulatory agonist, GRP. Incubation of myometrium with GRP receptor antagonists attenuates the effect of stretch. GRP may be a target for novel therapies to reduce the risk of preterm birth in multiple pregnancy.

Synchronous epithelial and neuroendocrine cancers of the pancreas: case series of a rare occurrence

The presence of neuroendocrine cells in adenocarcinomas is not an unusual finding and is well described in gastrointestinal tract cancers, eg, colorectal cancer and gastric cancer. Genetic analysis of such tumors has suggested a common multipotent progenitor stem cell origin. The prognostic significance of neuroendocrine cells in adenocarcinoma cells is unclear. There is a scant literature on synchronous pancreas ductal adenocarcinoma and pancreas neuroendocrine tumors. We report 2 cases with a purpose of discussing management strategies, prognosis, and potential etiologies of this rare presentation.

Proteases present in some pancreatic cyst fluids may affect mucin immunoassay by degrading antibodies and antigens

OBJECTIVES

Biomarker detection in pancreatic cyst fluids is of importance to improve the diagnosis of mucinous cystadenoma, a precancerous lesion. However, assay protocols are generally established for serum testing.

METHODS

Immunoradiometric assay of gastric M1/MUC5AC mucin was performed on pancreatic cyst fluids with well-characterized monoclonal antibodies.

RESULTS

Among 1466 pancreatic cyst fluids tested, about 10% to 15% of samples presented abnormal behaviors: (i) radioactivity measured after immunoradiometric assay much lower than the blank of the assay and (ii) increasing dilution of the fluids leading to apparent increase of M1/MUC5AC concentration. In contrast, none of the 109 hepatic cyst fluids tested presented interference.We demonstrate that some (n = 54) interfering fluids cause mucin degradation as well as antibody degradation. Western blot analysis showed that the C-terminal part of the M1/MUC5AC apomucin is most sensitive to degradation.

CONCLUSIONS

The presence of proteases that degrade antibodies as well as mucin may explain the pitfalls observed in 3.6% of the samples. To detect this interference, each fluid has to be systematically tested at 1:100 dilution in the presence of a saturating concentration of M1/MUC5AC mucin standard and in the absence of antiprotease reagents. Detection of interference could prevent false results caused by mucin degradation in situ.

Pancreatic duct glands are distinct ductal compartments that react to chronic injury and mediate Shh-induced metaplasia

BACKGROUND & AIMS

Pancreatic intraepithelial neoplasia (PanIN) are pancreatic cancer precursor lesions of unclear origin and significance. PanIN aberrantly express sonic hedgehog (Shh), an initiator of pancreatic cancer, and gastrointestinal mucins. A majority of PanIN are thought to arise from ducts. We identified a novel ductal compartment that is gathered in gland-like outpouches (pancreatic duct glands [PDG]) of major ducts and characterized its role in injury and metaplasia.

METHODS

The ductal system was analyzed in normal pancreata and chronic pancreatitis in humans and mice. Anatomy was assessed by serial hematoxylin and eosin sections and scanning electron microscopy of corrosion casts. Expression of mucins and developmental genes and proliferation were assessed by immunohistochemistry or real-time quantitative polymerase chain reaction. Effects of Shh on ductal cells were investigated by exposure to Shh in vitro and transgenic misexpression in vivo.

RESULTS

Three-dimensional analysis revealed blind-ending outpouches of ducts in murine and human pancreata. These PDG are morphologically and molecularly distinct from normal ducts; even in normal pancreata they display PanIN and metaplastic features, such as expression of Shh and gastric mucins. They express other developmental genes, such as Pdx-1 and Hes-1. In injury, Shh is up-regulated along with gastric mucins. Expansion of the PDG compartment results in a mucinous metaplasia. Shh promotes this transformation in vitro and in vivo.

CONCLUSIONS

PDG are distinct gland-like mucinous compartments with a distinct molecular signature. In response to injury, PDG undergo an Shh-mediated mucinous gastrointestinal metaplasia with PanIN-like features. PDG may provide a link between Shh, mucinous metaplasia, and neoplasia.

Molecular pathology of pancreatic cancer: implications for molecular targeting therapy

Pancreatic cancer develops through ductal dysplastic lesions or pancreatic intraepithelial neoplasia (PanIN). The origin of pancreatic cancer remains controversial. Some of the molecular origins of pancreatic cancer have been described. For example, KRAS, SHH, CDKN2A, TP53, SMAD4, and DUSP6 are crucial molecules in the development and progression of pancreatic cancer. Understanding the mechanisms of carcinogenesis could help researchers find the Achilles' heel of pancreatic cancer. Molecular targeting is a promising strategy for curing this devastating disease.

Serum pepsinogen level, atrophic gastritis and the risk of incident pancreatic cancer--a prospective cohort study

BACKGROUND

Pancreatic cancer is a highly fatal disease without screening tests. Studies have suggested possible etiologic similarities between gastric and pancreatic cancers. Atrophic gastritis, a pre-malignant condition for gastric cancer, is characterized by low serum pepsinogen I (SPGI) level. We hypothesized that low SPGI level may be associated with an increased risk of pancreatic cancer and be a useful biomarker for the disease.

METHODS

Our analytic cohort included 20,962 participants in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC) who had SPGI level measured. Of these, 1663 (7.9%) subjects had low SPGI levels (<25 microg/l) and were invited for gastroscopy which was completed in 1059 (63.7%) participants. Atrophic gastritis was histologically confirmed in 1006 (95.0%) subjects. We used Cox proportional hazards regression to calculate the hazard ratios (HR) and 95% confidence intervals (CI) for pancreatic cancer.

RESULTS

During follow-up of up to 16.3 years (mean=10.8 years; 226,325 person-years), 227 incident pancreatic cancers were diagnosed. The incidence rates were 9.9, 11.3, and 12.7 per 10,000 person-years of follow-up for participants with normal pepsinogen level (> or = 25 microg/l), low pepsinogen level and histologically confirmed atrophic gastritis, respectively. Compared to subjects with normal pepsinogen levels, there was no statistically significant increased risk of pancreatic cancer among subjects with low pepsinogen level (adjusted HR=1.01; 95% CI: 0.63-1.62) or those with histologically confirmed atrophic gastritis (adjusted HR=1.13; 95% CI: 0.66-1.95).

CONCLUSIONS

Atrophic gastritis, serological or histological, is not associated with increased risk of pancreatic cancer. These findings do not provide any evidence for potential usefulness of SPGI for pancreatic cancer screening.

Emerging functional roles of cathepsin E

Cathepsin E is an intracellular aspartic protease of the endolysosomal pathway. It has been implicated in several physiological and pathological processes however, its exact functional role is yet to be elucidated. The present review gives an account of the major physiological functions that are associated to cathepsin E by various research groups and highlights the conditions developed in cathepsin E deficiency or the conditions where overexpression of cathepsin E is observed.

Neoplastic endocrine differentiation of pancreatic ductal adenocarcinoma in a metastatic lymph node: report of a case

The occurrence of non-neoplastic, scattered endocrine cells in pancreatic ductal adenocarcinoma (DAC) is thought to be a general phenomenon. Conversely, neoplastic endocrine differentiation (NED) of pancreatic DAC is extremely unusual. We report a case of NED in a metastatic lymph node from pancreatic DAC. This case is distinct because the main tumor of the pancreas was composed purely of DAC without endocrine differentiation, and the NED was found in only one of four metastatic peripancreatic lymph nodes. To our knowledge, no other such case has ever been reported. The patient was a 61-year-old woman who underwent pylorus-preserving pancreaticoduodenectomy for pancreatic head cancer. Some authors reported that pancreatic DAC with endocrine differentiation was associated with a better prognosis than DAC without endocrine differentiation. However, more cases must be studied to investigate the impact of NED of metastatic lymph nodes in pancreatic DAC.

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas: its histopathologic difference between 2 major types

Intraductal papillary mucinous neoplasm (IPMN) is a unique pancreatic neoplasm developing in the ductal system. Two major histologic subtypes have been reported, that is the gastric type and the intestinal type. However, their histopathologic features, especially those of the gastric type, have not been fully described. To evaluate the features of these two types and refine their differences, we analyzed 80 IPMNs including 50 cases of the gastric type and 30 cases of the intestinal type with mucin immunohistochemistry. By defining a main duct-type lesion as predominantly involving the main pancreatic duct with or without branch ducts, and a branch duct-type lesion as exclusively centered on branch ducts or consisting of a collection of small cystic lesions, gastric-type IPMNs were mostly branch duct-type lesions (98%), whereas the intestinal-type IPMNs were usually main duct type (73%). The histologic grade of the intestinal type was generally higher than that of the gastric type. The intestinal type was also characterized by frequent intraluminal nodular growth, and severe atrophy and fibrosis of the surrounding parenchyma with mucous lake formation. In contrast, pyloric glandlike structures at the base of the papillae and pancreatic intraepithelial neoplasia (PanIN)-like complexes were more frequently observed in the gastric type. A significant difference was observed between the gastric type and the intestinal type with regard to all the above features (P<0.05). Seven cases (23%) of the intestinal type were associated with an invasive adenocarcinoma (6 mucinous and 1 ductal), versus only 1 case (2%) of the gastric type (invasive ductal carcinoma). All cases of both gastric and intestinal types expressed MUC5AC; however, high immunolabeling scores for MUC2 were mostly observed in the intestinal type (P<0.05). In conclusion, gastric and intestinal types of IPMNs have distinct histopathologic features and mucin profiles, suggesting that they may follow different biologic pathways.

Podocalyxin-like protein 1 expression is useful to differentiate pancreatic ductal adenocarcinomas from adenocarcinomas of the biliary and gastrointestinal tracts

Metastases of adenocarcinomas from the pancreas, liver, and gastrointestinal tract are difficult to distinguish from each other because of their similar morphological and immunohistochemical features. So far, no specific marker for pancreatic ductal adenocarcinomas has been described. Podocalyxin-like protein 1 (PODXL-1) is expressed on vascular endothelium, hematopoietic precursor cells, and renal podocytes. We found that 44% (71/160) of pancreatic ductal adenocarcinomas expressed PODXL-1 in a membranous pattern. There was no expression in intrahepatic cholangiocarcinomas (0/18, P < .001), rarely in adenocarcinomas of the extrahepatic bile ducts (1/13, P = .009), and none in duodenal adenocarcinomas (0/5, P = .070). PODXL-1 expression was seen in only 9% of hepatocellular carcinomas (5/56, P < .001), 9% (4/47, P < .001) of gastric carcinomas, 10% of esophageal adenocarcinomas (2/20, P = .003), and 6% of colonic adenocarcinomas (1/17, P = .001). When used as a differential diagnostic marker, ampullary carcinoma needs to be excluded, as 30% (6/20, P = .24) of ampullary carcinomas stain positive, especially those of the signet-ring type (3/3). Adenocarcinomas of the lung and prostate, and liver metastases of colorectal carcinomas lacked PODXL-1 expression. It is concluded that immunoreactivity for PODXL-1 favors a pancreatic origin if ampullary carcinoma is excluded.

Human pancreatic mucinous cystadenoma is characterized by distinct mucin, cytokeratin and CD10 expression compared with intraductal papillary-mucinous adenoma

AIMS

To examine cytokeratin, epithelial glycoprotein (mucin) and glycoprotein CD10 expression in benign mucinous cystdenomas (MCAs) in comparison with intraductal papillary mucinous adenomas (IPMAs).

METHODS AND RESULTS

Thirty MCAs of the pancreas were analysed for immunohistochemical expression of cytokeratin (CK) 7, CK20, MUC1, MUC2, MUC5AC and CD10 and were compared with 16 IPMAs. CK7 was expressed in all neoplasms. CK20 was significantly more frequent in MCAs compared with IPMAs (56.66% versus 18.75%, P = 0.027). MUC1 was more frequent in MCAs (40% versus 12.5%, P = 0.0915), whereas MUC5AC was significantly less frequent in MCAs (33.33% versus 100%). MUC2 was expressed in goblet cells of seven MCAs. In MCAs, CD10 was observed both in epithelial cells and in the ovarian-type stromal cells (24/30). Epithelial expression of CD10 was significantly lower in IPMAs (66.66% versus 6.25%, p = 0.0001).

CONCLUSIONS

MCA is characterized by a significantly greater frequency of expression of CK20 and CD10 when compared with IPMA, which preferentially expresses MUC5AC.

Gastrin-releasing peptide and cancer

Over the past 20 years, abundant evidence has been collected to suggest that gastrin-releasing peptide (GRP) and its receptors play an important role in the development of a variety of cancers. In fact, the detection of GRP and the GRP receptor in small cell lung carcinoma (SCLC), and the demonstration that anti-GRP antibodies inhibited proliferation in SCLC cell lines, established GRP as the prototypical autocrine growth factor. All forms of GRP are generated by processing of a 125-amino acid prohormone; recent studies indicate that C-terminal amidation of GRP18-27 is not essential for bioactivity, and that peptides derived from residues 31 to 125 of the prohormone are present in normal tissue and in tumors. GRP receptors can be divided into four classes, all of which belong to the 7 transmembrane domain family and bind GRP and/or GRP analogues with affinities in the nM range. Over-expression of GRP and its receptors has been demonstrated at both the mRNA and protein level in many types of tumors including lung, prostate, breast, stomach, pancreas and colon. GRP has also been shown to act as a potent mitogen for cancer cells of diverse origin both in vitro and in animal models of carcinogenesis. Other actions of GRP relevant to carcinogenesis include effects on morphogenesis, angiogenesis, cell migration and cell adhesion. Future prospects for the use of radiolabelled and cytotoxic GRP analogues and antagonists for cancer diagnosis and therapy appear promising.

Cathepsin E is a specific marker of dysplasia in APC mouse intestine

Transcriptional profiling of APC(Min/+) mouse intestinal epithelial tissue has revealed that cathepsin E (catE) manifests high relative expression in adenomas and carcinomas relative to normal epithelium. Real-time RT-PCR data presented previously confirm the presence of catE transcript in APC(Min/+) adenomatous cells compared with samples derived from normal APC(Min/+) and wild-type tissue. At the protein level, strong, highly specific immunohistochemical staining for catE is displayed in dysplastic lesions of APC(Min/+) mice. Using Western immunoblot analyses, it was additionally established that the urine of tumor-bearing mice contains higher levels of the monomeric form of catE than their wild-type counterparts. These results authenticate the relationship between transcript abundance and protein levels in transformed tissue and suggest potential utility for catE as a marker for the inception and progression of intestinal cancers.

[Cystic pancreas tumors and their classification: features old and new]

Cystic tumors and tumor-like lesions of the pancreas are rare, but have attracted a great deal of attention because they are easily recognized with new imaging methods and, in contrast to ductal adenocarcinoma, they can usually be cured surgically. The increasing resection rate in recent years has also increased our knowledge of cystic pancreatic tumors by conspicuously enlarging their morphological spectrum. Known entities have been better characterized (i.e. solid pseudopapillary neoplasm, intraductal papillary mucinous neoplasm) and new ones described (serous oligocystic adenoma, mucinous non-neoplastic cyst, acinar cell cystadenoma and cystic hamartoma). This review discusses the most important cystic tumors and tumor-like lesions, presents a new classification, and summarizes the immunohistochemical differential diagnosis.

Aberrant expression of cdx2 homeobox gene in intraductal papillary-mucinous neoplasm of the pancreas but not in pancreatic ductal adenocarcinoma

OBJECTIVES

The authors investigated differential expression of cdx2 in intraductal papillary mucinous neoplasm of the pancreas (IPMN) and ductal adenocarcinoma.

METHODS

Patients with IPMN (n = 23) and pancreatic ductal adenocarcinoma (n = 30) were studied. Expression of cdx2 mRNA, CDX2 protein, muc2 mRNA, MUC2 apomucin, and MUC5AC apomucin were determined.

RESULTS

Of 23 IPMN, expression of cdx2 was detected in 8 of 9 adenomas, 6 of 8 borderline malignancies, and 3 of 6 malignancies, respectively. Of the 3 cdx2-expressing malignant IPMN, 2 did not display CDX2 expression. The appearance of CDX2-positive neoplastic cells in IPMN coincided with that of MUC2-positive neoplastic cells. All 23 IPMN displayed a positive MUC5AC expression irrespective to the status of CDX2 expression. Of 30 ductal adenocarcinomas, none displayed cdx2, CDX2, and MUC2 expression, while 10 cases displayed positive MUC5AC expression.

CONCLUSION

Aberrant expression of cdx2 homeobox gene was detected in IPMN but not in ductal adenocarcinoma, which might determine their diverse carcinogenesis.

Intraductal tubular neoplasms of the pancreas: histogenesis and differentiation

OBJECTIVES

Intraductal neoplasms of the pancreas are generally referred to as intraductal papillary mucin-producing neoplasms (IPMNs), according to the WHO classification system. Herein, we report that morphologic and immunohistochemical features of intraductal tubular carcinoma (ITC) are quite different from those of intraductal papillary mucinous carcinoma (IPMC).

METHODS

We analyzed histogenesis and differentiation of ITC by light microscopy and immunohistochemistry.

RESULTS

Histologically, ITC was characterized as an intraductal nodular appearances with a monotonous tubular growth pattern without papillary projection. ITC showed de novo-like appearance without sequential progression usually observed in IPMC, suggesting that ITC is a homogeneous neoplasm. Cuboidal tumor cells in ITC resembled normal pancreatic duct epithelia, and the characteristic growth pattern of ITC replaced that of normal pancreatic duct epithelium. Immunohistochemically, ITC cells were positive for MUC-1 on the apical side of the cell membrane. In contrast to ITC cells, IPMC cells were negative for MUC-1, and ductal adenocarcinoma cells were strongly positive for MUC-1, as was the stroma around the cancer. The immunohistochemical staining pattern of DUPAN-2 resembled that of MUC-1. Interestingly, localization of MUC-1 and DUPAN-2 staining in ITC cells was similar to that in normal pancreatic ductules. ITC cells were negative for MUC-2 and MUC-5AC. In contrast, most IPMC cells were positive for MUC-2 and MUC-5AC.

CONCLUSION

Based on our histologic and immunohistochemical findings, the intraductal pancreatic neoplasm (IPN) can be classified into 2 groups: IPN with gastrointestinal differentiation and IPN with pancreatic duct differentiation. Our present data indicated that ITC cells may arise directly from duct epithelia without progression and possessed pancreatic duct differentiation. On the basis of our data, we suggest that classification of pancreatic neoplasms in the WHO and The Armed Forces Institute of Pathology (AFIP) systems should be reconsidered.

Histologic and immunohistochemical comparison of intraductal tubular carcinoma, intraductal papillary-mucinous carcinoma, and ductal adenocarcinoma of the pancreas

OBJECTIVE

To analyze the differences between intraductal tubular carcinoma (ITC) and intraductal papillary-mucinous carcinoma (IPMC), we performed light microscopic and immunohistochemical analysis of 4 cases of ITC, 6 cases of IPMC, and 9 cases of ductal adenocarcinoma of the pancreas.

METHODS AND RESULTS

Light microscopic examination showed no hyperplasia or adenoma around the carcinoma in ITC, and immunohistochemical analysis showed that the apical side of the cell membrane was positive for MUC-1 in almost all ITC cells. In contrast to ITC cells, all IPMC cells were negative for MUC-1 and ductal adenocarcinoma cells were strongly positive for MUC-1 in the cytoplasm and cell membrane. Immunohistochemical staining patterns of DUPAN-2 in ITC resembled those of MUC-1 in these cancers. ITC and IPMC cells were negative for carcinoembryonic antigen, but ductal adenocarcinoma cells were positive. There were no apparent differences in proliferative activity between ITC and IPMC, but ductal adenocarcinoma showed significantly greater activity than either ITC or IPMC.

CONCLUSION

The PCNA-L.I of IPMC and ITC was lower and the cell atypia of them was more mild compared with those of ductal carcinoma, indicating that IPMC possess low-grade malignant potentials. However, we observed differences of growth patterns and mucous secretion between ITC and IPMC of the pancreas.

Profiling, comparison and validation of gene expression in gastric carcinoma and normal stomach

Gastric carcinoma is the fourth most common cause of cancer death worldwide but its molecular biology is poorly understood. We catalogued the genes expressed in two gastric adenocarcinomas and normal stomach, using serial analysis of gene expression (SAGE), and compared the profiles on-line with other glandular epithelia. Candidates were validated by Northern blotting and immunohistochemistry. A total of 29 480 transcripts, derived from 10 866 genes, were identified. In all, 1% of the genes were differentially expressed (>/=fivefold difference plus P-value </=0.01) between cancers and normal stomach. The most abundant transcripts included ribosomal and mitochondrial proteins, of which most were upregulated in the tumours, as were other widely expressed genes including transcription factors, signalling molecules (serine/threonine protein kinases), thymosin beta 10 and collagenase I. Transcripts abundant in normal stomach were functionally important, including gastrin, immunoglobulin alpha, lysozyme, MUC5, pS2 and pepsinogens, which were among 55 gastric-specific genes. Many transcripts were minimally characterized or new, some cancer-associated genes reflected their intestinal morphology, and some normal gastric genes had previously been considered as pancreatic carcinoma markers. The gastric carcinoma profiles resembled other tumours', supporting the existence of common cancer-associated targets. These data provide a catalogue from which to develop markers for better diagnosis and therapy of gastric carcinoma.

Microsatellite instability and p53 expression in gallbladder carcinomas

We studied the MSI (microsatellite instability) status and p53 expression in a series of 71 gallbladder cancers (GCs) of different histologic type. All neoplasms were examined combining a microsatellite analysis at mononucleotide locus BAT-26 and an immunohistochemical study for hMSH2, hMLH1, and p53 proteins and markers of gastric and intestinal differentiation. All the 71 GCs were MSS (microsatellite stable). The p53 protein was found in 100% of undifferentiated GCs, 67% of conventional gallbladder adenocarcinomas, 50% of mucinous adenocarcinomas, and 20% GCs with squamous differentiation. All 71 MSS tumors showed presence of immunohistochemical expression of both hMLH1 and hMSH2 gene products. We concluded that microsatellite instability does not play a role in the developing of GC while p53 seems to be the most important alteration found in a large proportion of these cancers, with the only exception of mucinous and squamous gallbladder carcinomas.

Ductulo-insular pancreatic endocrine neoplasms: clinicopathologic analysis of a unique subtype of pancreatic endocrine neoplasms

Pancreatic neoplasms with mixed ductal and endocrine components are a heterogeneous group of tumors. The least recognized of these are pancreatic endocrine tumors (PETs) displaying benign-appearing tumor-associated ductules. To characterize these ductulo-insular pancreatic endocrine tumors (DI-PETs), we reviewed a series of 92 resected PETs. To be considered as a DI-PET we required the presence and tight intermingling of ductules with the dominant endocrine component (including the presence of ductulo-insular units). A total of 15 PETs fulfilled our criteria (16.3%). The average age of the DI-PET patients was similar to typical PETs (54 years vs 56 years). These tumors were smaller and more often insulin positive than typical PETs (p <0.05). Diffuse stromal fibrosis was more frequent in DI-PETs (11 of 15; 73.3.7%) compared with PETs (8 of 72; 11.1%) (p <0.05). The tumor-associated ductules were composed of cuboidal cells with dense eosinophilic cytoplasm and round nuclei without atypia or mitoses. They were positive for cytokeratin 7 and cytokeratin 19 and lacked any neuroendocrine markers. Reversibly, the endocrine component was negative for cytokeratin 7 and cytokeratin 19 and positive for neuroendocrine markers. Ultrastructural examination of ductulo-insular units confirmed a dual ductal and endocrine differentiation with amphicrine differentiation in one case. Follow-up was available in 12 cases with an average follow-up of 70.1 months (range 25-203 months). Ten patients are currently alive, and two patients died 81 and 158 months after surgery. We conclude that DI-PETs are not uncommon and that they are biologically similar to other PETs. We also hypothesize that the ductal cells develop by transdifferentiation of the endocrine cells.

Mixed ductal-endocrine carcinomas of the pancreas and ductal adenocarcinomas with scattered endocrine cells: characterization of the endocrine cells

We compared the histological and immunohistochemical features of mixed ductal-endocrine carcinomas of the pancreas with those of ductal adenocarcinomas (DACs) containing scattered tumor-associated endocrine cells (SECs). Three pancreatic neoplasms fulfilled the WHO criteria for mixed ductal-endocrine carcinomas. Two of them showed moderately to poorly differentiated glandular structures composed of both mucin producing and neuroendocrine cells. The third mixed ductal-endocrine carcinoma was of the composite type showing DAC structures and a solid component with small epithelial cells, most of them of neuroendocrine nature. In 32 of 34 cases of DAC located in the head (30 cases) and body to tail (4 cases) of the pancreas and showing lymph-node metastases, SECs were found, but they were few in number and irregularly distributed in the tumors. In three DACs a few SECs were also detected in lymph-node metastases. Double staining for chromogranin A and the proliferation marker Ki-S5 revealed that all SECs that were not intimately integrated into the neoplastic glandular epithelium failed to show proliferative activity and changes of the expression of tumor suppressor genes (p53 and DPC 4). These findings suggest that only those SECs that belong to the proliferative cell fraction may be of neoplastic origin, while the majority of SECs probably constitute a tumor-associated but non-neoplastic cell population. These features contrast with those of mixed ductal-endocrine carcinomas, in which all endocrine cells are a component of the neoplasm.

Involvement of 1p36 region in two cases of adenocarcinoma of the ampulla of Vater

Cancer of the ampulla of Vater is an uncommon disease that leads to death in 60% of affected patients. There is general agreement that local spread of the tumour (T stage) is the only significant and independent prognostic factor for this cancer. Although the genetic mechanisms underlying the development of ampullary tumors are still mostly unknown because of their rarity, the genetic anomalies involved in tumor development might serve as additional prognostic markers. Cytogenetic studies may be helpful in identifying specific chromosome regions involved in these cancers. We studied two cases of poorly differentiated ampullary adenocarcinomas using conventional and molecular cytogenetics on direct preparations. The cytogenetic analysis revealed complex chromosome complements in both cases with different cell lines, rearrangements, chromosome markers, and aneuploidies. Interestingly, the involvement of the 1p36 region was a feature of both cases. The molecular studies showed an absence of high microsatellite instability (MSI) and the morphologic and immunohistochemical pattern did not suggest MSI. This study may help to characterized ampullary adenocarcinomas showing complex karyotypes, poor differentiation and poor prognosis. In these tumors, the 1p36 region may play a relevant role in the progression towards a high grade of anaplasia.

Cystic lesions and neoplasms of the pancreas. The features are becoming clearer

This review focuses on the most common cystic pancreatic lesions and neoplasms (i.e. pseudocysts, intraductal papillary-mucinous neoplasms, mucinous cystic neoplasms, serous cystic neoplasms, solid pseudopapillary neoplasms and ductal adenocarcinomas with cystic features) and discusses their clinicopathological features. The progress made in recent years has made it possible to clearly distinguish between the various entities and to unravel some of the problems involved.

Characterization of gene expression profiles in intraductal papillary-mucinous tumors of the pancreas

The molecular pathology of precursor lesions leading to invasive pancreatic ductal adenocarcinomas remains relatively unknown. We have applied cDNA microarray analysis to characterize gene expression profiles in a series of intraductal papillary-mucinous tumors (IPMTs) of the pancreas, which represents one of the alternative routes of intraepithelial progression to full malignancy in the pancreatic duct system. Using a cDNA microarray containing 4992 human genes, we screened a total of 13 IPMTs including nine noninvasive and four invasive cases. Expression change in more than half of the tumors was observed for 120 genes, ie, 62 up-regulated and 58 down-regulated genes. Some of the up-regulated genes in this study have been previously described in classical pancreatic carcinomas such as lipocalin 2, galectin 3, claudin 4, and cathepsin E. The most highly up-regulated genes in IPMTs corresponded to three members of the trefoil factor family (TFF1, TFF2, and TFF3). Immunohistochemistry performed on five genes found to be differentially expressed at the RNA level (TFF1, TFF2, TFF3, lipocalin 2, and galectin 3) showed a good concordance between transcript level and protein abundance, except for TFF2. Hierarchical clustering organized the cases according to the dysplastic and invasive phenotype of theIPMTs. This analysis has permitted us to implicate several genes (caveolin 1, glypican 1, growth arrest-specific 6 protein, cysteine-rich angiogenic inducer 61) in tumor progression. The observation that several genes are differentially expressed both in IPMTs and pancreatic carcinomas suggests that they may be involved at an early stage of pancreatic carcinogenesis.

Cell lineage specificity of newly raised monoclonal antibodies against gastric mucins in normal, metaplastic, and neoplastic human tissues and their application to pathology diagnosis

The specificity of monoclonal antibodies against gastric mucins (designated as HIK1083, PGM 36, and PGM 37) was studied immunohistochemically in normal, metaplastic, and neoplastic human tissues. These antibodies labeled class III mucin-producing cells identified by paradoxical concanavalin A staining in normal stomach, duodenum (Brunner gland), biliary tract, and main pancreatic duct; in mucinous metaplasia of pancreas and gallbladder; and in adenocarcinomas of stomach (90%), bile duct (80%), gallbladder (100%), pancreas (80%), lung (100% of goblet cell type adenocarcinomas), ovary (67% of mucinous carcinomas), and uterine cervix (100% of adenoma malignum tumors). Normal and neoplastic cells of esophagus, colon, salivary gland, kidney, endometrium, breast, prostate, and liver, as well as normal small intestine, lung, and uterine cervix, were all negative. The antibodies used should be valuable for the detection of class III mucin and class III mucin-producing cells in normal, metaplastic, and neoplastic tissues.