Pancreatic intraepithelial neoplasia revisited and updated

[New insights into the origin of pancreatic cancer. Role of atypical flat lesions in pancreatic carcinogenesis]

The identification and characterization of precursor lesions is fundamental to develop screening programs for early diagnosis and treatment, aiming at reducing cancer-related mortality. Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease that becomes clinical apparent only in advanced stages. In order to enable screening procedures for early detection of PDAC, an exact characterization of precursor lesions is of utmost importance. Pancreatic intraepithelial neoplasias (PanIN) are the most frequent and best characterized precursors of PDAC and are lesions with a ductal phenotype thus indicating a ductal cell origin of PDAC. However, evidence from genetically engineered mouse models suggests that tubular complexes (TC) originating through a process of acinar-ductal metaplasia (ADM) form atypical flat lesions (AFL) that may represent an alternative pathway of pancreatic carcinogenesis. Based on a thorough morphological and genetic analysis of murine TC, AFL and PanIN and their human counterparts, a new dual model of pancreatic carcinogenesis is proposed taking into account the role of AFL as possible new precursors of PDAC.

LCN2 and TIMP1 as Potential Serum Markers for the Early Detection of Familial Pancreatic Cancer

High-risk individuals of familial pancreatic cancer (FPC) families are considered to be good candidates for screening programs to detect early PC or its high-grade precursor lesions, especially pancreatic intraepithelial neoplasia (PanIN) 2/3 lesions. There is a definite need for diagnostic markers as neither reliable imaging methods nor biomarkers are available to detect these lesions. On the basis of a literature search, the potential serum markers neutrophil gelatinase-associated lipocalin (LCN2), metallopeptidase inhibitor 1 (TIMP1), chemokine (C-X-C motif) ligand 16 (CXCL16), IGFBP4, and iC3a, which were first tested in transgenic KrasLSL.(G12D/+);p53(R172H/+);Pdx1-Cre mice, were identified. ELISA analyses of LCN2, TIMP1, and CXCL16 revealed significantly higher levels in mice with PanIN2/3 lesions or PC compared to mice with normal pancreata or PanIN1 lesions. Analysis of preoperative human serum samples from patients with sporadic PC (n = 61), hereditary PC (n = 24), chronic pancreatitis (n = 28), pancreatic neuroendocrine tumors (n = 11), and FPC patients with histologically proven multifocal PanIN2/3 lesions (n = 3), as well as healthy control subjects (n = 20), confirmed significantly higher serum levels of LCN2 and TIMP1 in patients with PC and multifocal PanIN2/3 lesions. The combination of LCN2 and TIMP1 as a diagnostic test for the detection of PC had a sensitivity, specificity, and positive predictive value of 100% each. Although this preliminary finding needs to be validated in a large series of individuals at high risk for FPC, serum measurement of LCN2 and TIMP1 might be a promising screening tool.

[Chronic pancreatitis with pseudocysts?]

The gross examination of cystic changes in chronic pancreatitis can cause diagnostic problems particularly in the absence of grossly detectable tumor tissue. Besides the more frequently encountered pancreatitis-associated pseudocysts, pancreatic cysts should always raise attention to the differential diagnosis of a true neoplastic process.

Molecular markers in pancreatic cancer diagnosis

Pancreatic ductal adenocarcinoma (PDAC) represents a fatal neoplasia with a high mortality rate. Effective early detection methods are needed since this is the best way to cure this disease. During the last several years, many investigations focused on determining relevant biomarkers that may be present during early stages of pancreatic tumor development. Although several biomarkers have been proposed for pancreatic cancer detection, the clinical applicability has been confusing. Currently, although CA19-9 is one test used, the sensitivity and specificity for the disease are less than optimal. Here, we review several new potential serum, plasma and stool markers that are currently under evaluation. Although these have not been sufficiently validated for routine clinical use, these markers could prove valuable with further investigations. We keep the hope that a combination of some of these novel biomarkers can be a useful tool for early PDAC diagnosis before image techniques and/or patient's symptoms reveal disease in an incurable state.

The prevention and genetics of pancreatic cancer: a programmatic approach

Pancreatic cancer (PC) is typically a fatal disease due to its rapid growth and the lack of early diagnostic -techniques. Because approximately 10% of PCs are attributable to a hereditary susceptibility, identifying and studying patients with a family history of PC or known genetic predisposition to PC can improve the prevention, diagnosis, and treatment of PC. A skilled team of study investigators, physicians, genetic counselors, and data managers must work with patients and families to confidentially store and organize data from PC patients and high-risk patients. This data, collected in conjunction with patients' tissue and blood specimens, will contribute to the understanding of the biology, etiology, and epidemiology of PC, and can ultimately improve screening and management for patients with an underlying hereditary predisposition to PC.

Digital quantification of precursor frequency in the fallopian tube and its significance

A high frequency of precursor lesions is a risk factor for cancer in many organ systems but must be precisely quantified. Pelvic serous neoplasia is associated with an estimated increase in frequency of secretory cell outgrowths (SCOUTs) with loss of PAX2 protein (PAX2p) expression (PAX2p-null SCOUTs) in the fallopian tube. However, to confirm this, PAX2p-null SCOUTs must be precisely quantified relative to the epithelial surface. We developed a method by which fallopian tube sections were digitized using an iScan brightfield scanner (BioImagene) and uploaded in Adobe Photoshop CS3 Extended. Pixel length was translated into microns and epithelial length measured with the Magic Wand tool. SCOUTs were expressed as a function of total epithelial perimeter. Frequency, required perimeter length, topographic clustering tendency and effects of age were ascertained. SCOUT frequency per 10 cm was 0-4.60 for cases and 0-1.66 for controls, averaging 0.84 and 0.27, respectively, (P=0.007). Required perimeter length for SCOUT detection was less in serous cancer cases and topographic distribution followed a random pattern without aberrant clustering. Age was also associated with SCOUT frequency (P=0.025) and differences between cancers and controls were still significant after adjusting for age (P=0.001). We describe an efficient method for quantifying epithelial perimeter in the fallopian tube and verify its relevance to precursor frequency. This has important implications for assessing precursor frequency both in the fallopian tube and in other organs-such as prostate, pancreas and colon-where epithelial precursors are integral to carcinogenesis.

Variation in precursor lesions of pancreatic cancer among high-risk groups

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) surveillance programs are currently offered to high-risk individuals aiming to detect precursor lesions or PDAC at an early stage. We assessed differences in frequency and behavior of precursor lesions and PDAC between two high-risk groups.

EXPERIMENTAL DESIGN

Individuals with a p16-Leiden germline mutation (N = 116; median age 54 years) and individuals from familial pancreatic cancer (FPC) families (N = 125; median age 47 years) were offered annual surveillance by MRI and magnetic resonance cholangiopancreatography (MRCP) with or without endoscopic ultrasound (EUS) for a median surveillance period of 34 months (0-127 months) or 36 months (0-110 months), respectively. Detailed information was collected on pancreatic cystic lesions detected on MRCP and precursor lesions in surgical specimens of patients who underwent pancreatic surgery.

RESULTS

Cystic lesions were more common in the FPC cohort (42% vs. 16% in p16-Leiden cohort), whereas PDAC was more common in the p16-Leiden cohort (7% vs. 0.8% in FPC cohort). Intraductal papillary mucinous neoplasm (IPMN) was a common finding in surgical specimens of FPC-individuals, and was only found in two patients of the p16-Leiden cohort. In the p16-Leiden cohort, a substantial proportion of cystic lesions showed growth or malignant transformation during follow-up, whereas in FPC individuals most cystic lesions remain stable.

CONCLUSION

In p16-Leiden mutation carriers, cystic lesions have a higher malignant potential than in FPC-individuals. On the basis of these findings, a more intensive surveillance program may be considered in this high-risk group.

Surveillance for gastrointestinal malignancies

Gastrointestinal (GI) malignancies are notorious for frequently progressing to advanced stages even in the absence of serious symptoms, thus leading to delayed diagnoses and dismal prognoses. Secondary prevention of GI malignancies through early detection and treatment of cancer-precursor/premalignant lesions, therefore, is recognized as an effective cancer prevention strategy. In order to efficiently detect these lesions, systemic application of screening tests (surveillance) is needed. However, most of the currently used non-invasive screening tests for GI malignancies (for example, serum markers such as alpha-fetoprotein for hepatocellular carcinoma, and fecal occult blood test, for colon cancer) are only modestly effective necessitating the use of highly invasive endoscopy-based procedures, such as esophagogastroduodenoscopy and colonoscopy for screening purposes. Even for hepatocellular carcinoma where non-invasive imaging (ultrasonography) has become a standard screening tool, the need for repeated liver biopsies of suspicious liver nodules for histopathological confirmation can’t be avoided. The invasive nature and high-cost associated with these screening tools hinders implementation of GI cancer screening programs. Moreover, only a small fraction of general population is truly predisposed to developing GI malignancies, and indeed needs surveillance. To spare the average-risk individuals from superfluous invasive procedures and achieve an economically viable model of cancer prevention, it’s important to identify cohorts in general population that are at substantially high risk of developing GI malignancies (risk-stratification), and select suitable screening tests for surveillance in these cohorts. We herein provide a brief overview of such high-risk cohorts for different GI malignancies, and the screening strategies that have commonly been employed for surveillance purpose in them.

Hepatitis B and C virus infections as possible risk factor for pancreatic adenocarcinoma

Pancreatic adenocarcinoma (PAC) is a very aggressive and lethal cancer, with a very poor prognosis, because of absence of early symptoms, advanced stage at presentation, early metastatic dissemination and lack of both specific tests to detect its growth in the initial phases and effective systemic therapies. To date, the causes of PAC still remain largely unknown, but multiple lines of evidence from epidemiological and laboratory researches suggest that about 15-20% of all cancers are linked in some way to chronic infection, in particular it has been shown that several viruses have a role in human carcinogenesis. The purpose of this report is to discuss the hypothesis that two well-known oncogenic viruses, Human B hepatitis (HBV) and Human C hepatitis (HCV) are a possible risk factor for this cancer. Therefore, with the aim to examine the potential link between these viruses and PAC, we performed a selection of observational studies evaluating this association and we hypothesized that some pathogenetic mechanisms involved in liver carcinogenesis might be in common with pancreatic cancer development in patients with serum markers of present or past HBV and HCV infections. To date the available observational studies performed are few, heterogeneous in design as well as in end-points and with not univocal results, nevertheless they might represent the starting-point for future larger and better designed clinical trials to define this hypothesized relationship. Should these further studies confirm an association between HBV/HCV infection and PAC, screening programs might be justified in patients with active or previous hepatitis B and C viral infection.

Gastric- and intestinal-type marker expression in invasive ductal adenocarcinoma of the pancreas

BACKGROUND

Although invasive ductal adenocarcinoma of the pancreas (PDAC) manifests as a relatively uniform histomorphological feature of the pancreatobiliary type, it may be complicated by metaplastic changes and heterogeneous gastric and intestinal elements. This study aimed to investigate the complication rate and clinicopathological significance of such heterogeneous elements.

METHODS

Fifty-nine patients who underwent resection of PDAC were examined in this study. Immunohistochemically, tumors showing high expression (>25%) of the intestinal-type (INT) marker CDX2 were classified as PDAC with INT. Those with high expression (>25%) of the gastric-type (GAS) marker MUC5AC were classified as PDAC with GAS, while those with high expression of both markers were classified as PDAC with INT/GAS. These patients were compared with those with PDAC of the negative group in which neither markers was highly expressed to examine their clinicopathological significance.

RESULTS

In the 59 patients, 31 (52.5%) showed high CDX2 or MUC5AC expression. Twenty-eight patients (47.5%) belonged to a negative group, 11 (18.6%) to a PDAC with INT group, 15 (25.4%) to a PDAC with GAS group, and 5 (8.5%) to a PDAC with INT/GAS group. No significant differences were observed for age, gender, size, localization, T classification, or prognosis among the four groups. Although the PDAC with GAS group had well differentiated types significantly more than the other groups, the rate of lymph node metastasis in this group was significantly higher (PDAC with GAS: 73%; other groups: 36%).

CONCLUSION

Complications with heterogeneous elements are not uncommon in PDAC, and this should be considered during the diagnosis and treatment of PDAC along with histogenesis of the disease.

The role of stroma in pancreatic cancer: diagnostic and therapeutic implications

Pancreatic ductal adenocarcinoma (PDAC) is one of the five most lethal malignancies worldwide and survival has not improved substantially in the past 30 years. Desmoplasia (abundant fibrotic stroma) is a typical feature of PDAC in humans, and stromal activation commonly starts around precancerous lesions. It is becoming clear that this stromal tissue is not a bystander in disease progression. Cancer-stroma interactions effect tumorigenesis, angiogenesis, therapy resistance and possibly the metastatic spread of tumour cells. Therefore, targeting the tumour stroma, in combination with chemotherapy, is a promising new option for the treatment of PDAC. In this Review, we focus on four issues. First, how can stromal activity be used to detect early steps of pancreatic carcinogenesis? Second, what is the effect of perpetual pancreatic stellate cell activity on angiogenesis and tissue perfusion? Third, what are the (experimental) antifibrotic therapy options in PDAC? Fourth, what lessons can be learned from Langton's Ant (a simple mathematical model) regarding the unpredictability of genetically engineered mouse models?

Chronic GLP-1 receptor activation by exendin-4 induces expansion of pancreatic duct glands in rats and accelerates formation of dysplastic lesions and chronic pancreatitis in the Kras(G12D) mouse model

Pancreatic duct glands (PDGs) have been hypothesized to give rise to pancreatic intraepithelial neoplasia (PanIN). Treatment with the glucagon-like peptide (GLP)-1 analog, exendin-4, for 12 weeks induced the expansion of PDGs with mucinous metaplasia and columnar cell atypia resembling low-grade PanIN in rats. In the pancreata of Pdx1-Cre; LSL-Kras(G12D) mice, exendin-4 led to acceleration of the disruption of exocrine architecture and chronic pancreatitis with mucinous metaplasia and increased formation of murine PanIN lesions. PDGs and PanIN lesions in rodent and human pancreata express the GLP-1 receptor. Exendin-4 induced proproliferative signaling pathways in human pancreatic duct cells, cAMP-protein kinase A and mitogen-activated protein kinase phosphorylation of cAMP-responsive element-binding protein, and increased cyclin D1 expression. These GLP-1 effects were more pronounced in the presence of an activating mutation of Kras and were inhibited by metformin. These data reveal that GLP-1 mimetic therapy may induce focal proliferation in the exocrine pancreas and, in the context of exocrine dysplasia, may accelerate formation of neoplastic PanIN lesions and exacerbate chronic pancreatitis.

Resection margin involvement and tumour origin in pancreatic head cancer

BACKGROUND

Assessment of the origin of adenocarcinoma in pancreatoduodenectomy specimens (pancreatic, ampullary or biliary) and resection margin status is not performed in a consistent manner in different centres. The aim of this review was to identify the impact of such variations on patient outcome.

METHODS

A systematic literature search for articles on pancreatic, ampullary, distal bile duct and periampullary cancer was performed, with special attention to data on resection margin status, pathological examination and outcome.

RESULTS

The frequent reclassification of tumour origin following slide review, and the wide variation in published incidence of pancreatic (33-89 per cent), ampullary (5-42 per cent) and distal bile duct (5-38 per cent) cancers indicate that the histopathological distinction between the three cancer groups is less accurate than generally believed. Recent studies have shown that the wide range of rates of microscopic margin involvement (R1) in pancreatoduodenectomy specimens (18-85, 0-27 and 0-72 per cent respectively for pancreatic, ampullary and distal bile duct cancers) is mainly caused by differences in pathological assessment rather than surgical practice and patient selection. As a consequence of the existing inconsistency in reporting of these data items, the clinical significance of microscopic margin involvement in each of the three cancer groups remains unclear.

CONCLUSION

Inaccurate and inconsistent distinction between pancreatic, ampullary and distal bile duct cancer, combined with inaccuracies in resection margin assessment, results in obfuscation of key clinicopathological data. Specimen dissection technique plays a key role in the quality of the assessment of both tumour origin and margin status. Unless the pathological examination is meticulous and standardized, comparison of results between centres and observations in multicentre trials will remain of limited value.

Very high CEA level in a large pancreatic cyst: is it a surgical indication by itself?

BACKGROUND

Pancreatic mucinous cystic lesions might develop malignancy if untreated, or could harbor malignancy at the time of the diagnosis. Many reports stated that cyst fluid carcinoembryonic antigen is an accurate diagnostic marker of pancreatic mucinous cysts.

METHODS

A man with a incidental pancretic cystic lesion of 35 mm in diameter was admitted to our Department. CT and EUS did not reveal solid components, main duct was not dilated and cyst fluid CEA was very high (1445 ng/ml).

RESULTS

The patient underwent a pancreatoduodenectomy and the surgical specimen showed a pseudocyst with columnar mucinous epithelium, consistent with low-grade PanIN.

CONCLUSIONS

Is it possible that the mucinous epithelium of panIN was responsible for the unexpectedly high CEA value? Clinicians should be aware of the usefulness of the CEA level in cystic fluid but even a very high CEA value should not be considered by itself to be evidence of a mucinous lesion.

Screening for pancreatic cancer in a high-risk cohort: an eight-year experience

BACKGROUND

Pancreatic adenocarcinoma is the fourth leading cause of cancer death.

METHODS

A prospective cohort study was undertaken between 2003 and 2011 at a tertiary care centre in Toronto, Canada. Two hundred and sixty-two subjects were enrolled based on an elevated estimated lifetime risk for pancreatic cancer due to known genetic mutations and/or cancer family history. Subjects underwent annual magnetic resonance imaging, followed by additional investigations if abnormal findings were detected. Evidence of malignancy or suspicious macroscopic abnormalities prompted referral for surgical intervention.

RESULTS

Average length of follow-up was 4.2 years, during which 84/262 (32%) subjects demonstrated pancreatic abnormalities. Three participants developed pancreatic adenocarcinoma (one 1.5-cm tumor was resected but recurred, while the other two subjects developed metastatic cancer), and a fourth participant developed a pancreatic neuroendocrine tumor that was resected. Fifteen subjects had radiologic evidence of branch-duct intraductal papillary mucinous neoplasms, of which two underwent surgical resection. Sixty-five subjects had simple pancreatic cysts that have remained stable.

CONCLUSION

Magnetic resonance imaging can detect small pancreatic tumors and cystic lesions, but further improvement in sensitivity is needed. An understanding of the natural history of pre-invasive lesions in members of high-risk families is necessary for developing a more effective screening program.

[Precursor lesions of pancreatobiliary cancer]

Precursor lesions of pancreatobiliary cancer can be divided into cystic and flat lesions. Mucinous cystic neoplasm and intraductal papillary mucinous neoplasm (IPMN) comprise the cystic precursors in the pancreas, while intraductal papillary neoplasm (IPN) represents their counterpart in the bile duct system. There is an adenoma-carcinoma sequence in the cystic precursors arising from four different types of epithelia: pancreatobiliary, oncocytic, intestinal and gastric. These subtypes of IPMN/IPN are morphologically and immunohistochemically well characterised and show clinical and prognostic relevance: the gastric subtype is associated with the best prognosis, followed by the oncocytic and intestinal subtypes, while the pancreatobiliary subtype is characterized by adverse clinical behaviour. Pancreatic intraepithelial neoplasia (PanIN) and biliary intraepithelial neoplasia (BilIN) represent the flat precursors. PanIN are morphologically and biologically well defined. PanIN with lobulocentric atrophy has recently been described as a putative precursor of pancreatic cancer. Despite well defined morphological features in BilIN, the molecular alterations seen during early tumor progression in the biliary tract are poorly understood.

Association of increased DNA methyltransferase expression with carcinogenesis and poor prognosis in pancreatic ductal adenocarcinoma

INTRODUCTION

Epigenetic modifications play an important role in multistage carcinogenesis. The role of the three functional DNA methyltransferases (DNMTs) in pancreatic carcinogenesis has not been fully understood. The main goal of this study was to examine DNMT expression in different stages of pancreatic ductal adenocarcinoma (PDAC), and evaluate their prognostic significance in PDAC.

MATERIALS AND METHODS

A large number of premalignant and malignant pancreatic lesions were obtained by manual microdissection. Quantitative real-time RT-PCR was used to detect DNMTs mRNA expression. Nonparametric test, logrank test and Cox regression analysis were used to evaluate the clinical significance of DNMT expression.

RESULTS

The mRNA expression of the three DNMTs increased with the development of pancreatic cancer from normal duct to pancreatic intraductal neoplasia and further to PDAC, and were statistically correlated with each other. Expression of the three DNMTs was statistically correlated with TNM staging and history of chronic pancreatitis. DNMT3A and DNMT3B, but not DNMT1 expression, was statistically correlated with tumour size. Patients with higher levels of DNMT1, DNMT3A and/or DNMT3B expression had an overall lower survival than those with lower levels of expression. Univariate analysis showed that high expression levels of DNMTs, alcohol consumption, tumour differentiation and TNM staging were statistically significant risk factors. Multivariate analysis showed that high level of DNMT3B expression and tumour differentiation were statistically significant independent poor prognostic factors.

CONCLUSIONS

These results suggested that pancreatic carcinogenesis involves an increased mRNA expression of three DNMTs, and they may become valuable diagnostic and prognostic markers as well as potential therapeutic targets for pancreatic cancer.

Origin of pancreatic ductal adenocarcinoma from atypical flat lesions: a comparative study in transgenic mice and human tissues

Pancreatic ductal adenocarcinoma (PDAC) and its precursor lesions, pancreatic intraepithelial neoplasia (PanIN), display a ductal phenotype. However, there is evidence in genetically defined mouse models for PDAC harbouring a mutated kras under the control of a pancreas-specific promoter that ductal cancer might arise in the centroacinar-acinar region, possibly through a process of acinar-ductal metaplasia (ADM). In order to further elucidate this model of PDAC development, an extensive expression analysis and molecular characterization of the putative and already established (PanIN) precursor lesions were performed in the Kras(G12D/+) ; Ptf1a-Cre(ex1/+) mouse model and in human tissues, focusing on lineage markers, developmental pathways, cell cycle regulators, apomucins, and stromal activation markers. The results of this study show that areas of ADM are very frequent in the murine and human pancreas and represent regions of increased proliferation of cells with precursor potential. Moreover, atypical flat lesions originating in areas of ADM are the most probable precursors of PDAC in the Kras(G12D/+); Ptf1a-Cre(ex1/+) mice and similar lesions were also found in the pancreas of three patients with a strong family history of PDAC. In conclusion, PDAC development in Kras(G12D/+); Ptf1a-Cre(ex1/+) mice starts from ADM and a similar process might also take place in patients with a strong family history of PDAC.

Genetic and epigenetic alterations in pancreatic carcinogenesis

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers worldwide. Despite significant progresses in the last decades, the origin of this cancer remains unclear and no efficient therapy exists. PDAC does not arise de novo: three remarkable different types of pancreatic lesions can evolve towards pancreatic cancer. These precursor lesions include: Pancreatic intraepithelial neoplasia (PanIN) that are microscopic lesions of the pancreas, Intraductal Papillary Mucinous Neoplasms (IPMN) and Mucinous Cystic Neoplasms (MCN) that are both macroscopic lesions. However, the cellular origin of these lesions is still a matter of debate.

Classically, neoplasm initiation or progression is driven by several genetic and epigenetic alterations. The aim of this review is to assemble the current information on genetic mutations and epigenetic disorders that affect genes during pancreatic carcinogenesis. We will further discuss the interest of the genetic and epigenetic alterations for the diagnosis and prognosis of PDAC. Large genetic alterations (chromosomal deletion/amplification) and single point mutations are well described for carcinogenesis inducers. Mutations classically occur within key regions of the genome. Consequences are various and include activation of mitogenic pathways or silencing of apoptotic processes. Alterations of K-RAS, P16 and DPC4 genes are frequently observed in PDAC samples and have been described to arise gradually during carcinogenesis. DNA methylation is an epigenetic process involved in imprinting and X chromosome inactivation. Alteration of DNA methylation patterns leads to deregulation of gene expression, in the absence of mutation. Both genetic and epigenetic events influence genes and non-coding RNA expression, with dramatic effects on proliferation, survival and invasion. Besides improvement in our fundamental understanding of PDAC development, highlighting the molecular alterations that occur in pancreatic carcinogenesis could provide new clinical tools for early diagnosis of PDAC and the molecular basis for the development of new effective therapies.

Pathologic complete response to neoadjuvant therapy in patients with pancreatic ductal adenocarcinoma is associated with a better prognosis

In patients with pancreatic ductal adenocarcinoma (PDA) who received neoadjuvant therapy and pancreatectomy, pathologic complete response (pCR) is rarely observed and the prognostic significance of pCR is not clear. In this study, we identified 11 patients with pCR (2.5%) from 442 patients with PDA who received neoadjuvant treatment and pancreatectomy from 1995 to 2010. There were 6 men and 5 women, with a median age of 61 years. Four patients had either synchronous or history of extrapancreatic cancer. Five patients received neoadjuvant chemotherapy followed by chemoradiation, and 6 received chemoradiation alone. Ten patients had pancreaticoduodenectomy, and 1 had distal pancreatectomy. Scar and chronic pancreatitis consistent with therapy effect were present in all cases (100%). Pancreatic intraepithelial neoplasia (PanIN) 3/carcinoma in situ was present in 5 cases, and PanIN1 and PanIN2 in 5 cases. However, no residual invasive carcinoma or lymph node metastasis was identified in all cases. Follow-up information was available in 10 patients. Follow-up time ranges from 6 to 194 months (median, 63 months). During the follow-up, 3 patients died of other causes, and 1 developed a second primary PDA in the tail of the pancreas at 84 months after the initial pancreaticoduodenectomy and died at 105 months after the initial diagnosis of PDA. The other 6 patients were alive with no evidence of disease. Patients with pCR had a better survival than did those who had posttherapy stage I or IIA disease (P < .001). Patients with PDA who received neoadjuvant therapy and had pCR in pancreatectomy are rare but have a better prognosis.

Precursor lesions in pancreatic cancer: morphological and molecular pathology

Pancreatic cancer has a dismal prognosis and is the fourth most common cause of cancer related death in Western societies. In large part this is due to its typically late presentation, usually as locally advanced or metastatic disease. Identification of the non-invasive precursor lesions to pancreatic cancer raises the possibility of surgical treatment or chemoprevention at an early stage in the evolution of this disease, when more amenable to therapeutic interventions. Precursor lesions to pancreatic ductal adenocarcinoma, in particular pancreatic intraepithelial neoplasia (PanIN), have been recognised under a variety of synonyms for over 50 years. Over the past decade our understanding of the morphology, biological significance and molecular aberrations of these lesions has grown rapidly and there is now a widely accepted progression model integrating the accumulated morphological and molecular observations. Further progress is likely to be accelerated by improved mouse models of pancreatic cancer and by insight into the cancer genome gained by the International Cancer Genome Consortium (ICGC), in which an Australian consortium is leading the pancreatic cancer initiative. This review also outlines the morphological and molecular features of the other two precursors of pancreatic ductal adenocarcinoma, i.e., intraductal papillary mucinous neoplasms and mucinous cystic neoplasms.

Overexpression of CXCL5 is associated with poor survival in patients with pancreatic cancer

Epithelial neutrophil-activating peptide-78 (CXCL5), a member of the CXC chemokine family, has been shown to be involved in angiogenesis, tumor growth, and metastasis. The objective of this study was to determine the relationship between CXCL5 expression and tumor progression in human pancreatic cancer and to elucidate the mechanism underlying CXCL5-mediated tumor angiogenesis and cancer growth. We report herein that CXCL5 is overexpressed in human pancreatic cancer compared with paired normal pancreas tissue. Overexpression of CXCL5 is significantly correlated with poorer tumor differentiation, advanced clinical stage, and shorter patient survival. Patients with pancreatic cancer and CXCL5 overexpression who underwent resection of cancer had a mean survival time 25.5 months shorter than that of patients who did not overexpress CXCL5. Blockade of CXCL5 or its receptor CXCR2 by small-interfering RNA knockdown or antibody neutralization attenuated human pancreatic cancer growth in a nude mouse model. Finally, we demonstrated that CXCL5 mediates pancreatic cancer-derived angiogenesis through activation of several signaling pathways, including protein kinase B (Akt), extracellular signal-regulated kinase (ERK), and signal transducer and activator of transcription (STAT) in human endothelial cells. These data suggest that CXCL5 is an important mediator of tumor-derived angiogenesis and that it may serve as a survival factor for pancreatic cancer. Blockade of either CXCL5 or CXCR2 may be a critical adjunct antiangiogenic therapy against pancreatic cancer.

Pancreatic ductal adenocarcinoma derived from IPMN and pancreatic ductal adenocarcinoma concomitant with IPMN

OBJECTIVES

Pancreatic ductal adenocarcinoma (PDAC) may derive from an intraductal papillary mucinous neoplasm (IPMN) of the pancreas or may develop in the pancreatic duct apart from IPMN. The purpose of this study was to define the clinicopathological features of these 2 entities and compare them with those of ordinary PDAC.

METHODS

Of 765 patients who had surgical resection for IPMN, 122 were diagnosed as having PDAC derived from IPMN and 31 with PDAC concomitant with IPMN. In addition, 7605 patients with PDAC who were registered in the Japan Pancreas Society pancreatic cancer registry were compared with the above patients.

RESULTS

Pancreatic ductal adenocarcinomas derived from IPMN and concomitant with IPMN were significantly smaller, less invasive, and less extensive than ordinary PDAC. The median survival of patients with the 2 conditions was significantly longer than for those with ordinary PDAC when compared overall or when limited to TS2 (2.0 cm < tumor size ≤ 4.0 cm) or TS3 (4.0 cm < tumor size ≤ 6.0 cm) cases.

CONCLUSIONS

These findings suggest that PDAC concomitant with IPMN and PDAC derived from IPMN may have more favorable biological behaviors or be diagnosed earlier than ordinary PDAC.

Precursor lesions of early onset pancreatic cancer

Early onset pancreatic cancer (EOPC) constitutes less than 5% of all newly diagnosed cases of pancreatic cancer (PC). Although histopathological characteristics of EOPC have been described, no detailed reports on precursor lesions of EOPC are available. In the present study, we aimed to describe histopathological picture of extratumoral parenchyma in 23 cases of EOPCs (definition based on the threshold value of 45 years of age) with particular emphasis on two types of precursor lesions of PC: pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasms (IPMNs). The types, grades, and densities of precursor lesions of PC were compared in patients with EOPCs, in young patients with neuroendocrine neoplasms (NENs), and in older (at the age of 46 or more) patients with PC. PanINs were found in 95.6% of cases of EOPCs. PanINs-3 were found in 39.1% of EOPC cases. Densities of all PanIN grades in EOPC cases were larger than in young patients with NENs. Density of PanINs-1A in EOPC cases was larger than in older patients with PC, but densities of PanINs of other grades were comparable. IPMN was found only in a single patient with EOPC but in 20% of older patients with PC. PanINs are the most prevalent precursor lesions of EOPC. IPMNs are rarely precursor lesions of EOPC. Relatively high density of low-grade PanINs-1 in extratumoral parenchyma of patients with EOPC may result from unknown multifocal genetic alterations in pancreatic tissue in patients with EOPCs.

Familial pancreatic cancer

Pancreatic cancer’s high mortality rate equates closely with its incidence, thereby showing the need for development of biomarkers of its increased risk and a better understanding of its genetics, so that high-risk patients can be better targeted for screening and early potential lifesaving diagnosis. Its phenotypic and genotypic heterogeneity is extensive and requires careful scrutiny of its pattern of cancer associations, such as malignant melanoma associated with pancreatic cancer, in the familial atypical multiple mole melanoma syndrome, due to the CDKN2A germline mutation. This review is designed to depict several of the hereditary pancreatic cancer syndromes with particular attention given to the clinical application of this knowledge into improved control of pancreatic cancer.

Current status of molecular markers for early detection of sporadic pancreatic cancer

Pancreatic cancer (PC) is a highly lethal malignancy with near 100% mortality. This is in part due to the fact that most patients present with metastatic or locally advanced disease at the time of diagnosis. Significantly, in nearly 95% of PC patients there is neither an associated family history of PC nor of diseases known to be associated with an increased risk of PC. These groups of patients who comprise the bulk of PC cases are termed as "sporadic PC" in contrast to the familial PC cases that comprise only about 5% of all PCs. Given the insidious onset of the malignancy and its extreme resistance to chemo and radiotherapy, an abundance of research in recent years has focused on identifying biomarkers for the early detection of PC, specifically aiming at the sporadic PC cohort. However, while several studies have established that asymptomatic individuals with a positive family history of PC and those with certain heritable syndromes are candidates for PC screening, the role of screening in identifying sporadic PC is still an unsettled question. The present review attempts to assess this critical question by investigating the recent advances made in molecular markers with potential use in the early diagnosis of sporadic PC - the largest cohort of PC cases worldwide. It also outlines a novel yet simple risk factor based stratification system that could be potentially employed by clinicians to identify those individuals who are at an elevated risk for the development of sporadic PC and therefore candidates for screening.

Immunohistochemistry for cell polarity protein lethal giant larvae 2 differentiates pancreatic intraepithelial neoplasia-3 and ductal adenocarcinoma of the pancreas from lower-grade pancreatic intraepithelial neoplasias

Pancreatic intraepithelial neoplasia is a precursor to ductal adenocarcinoma of the pancreas that shows gastric differentiation. Pancreatic intraepithelial neoplasia-3 has the highest potential to progress to adenocarcinoma, and its distinction from lower-grade pancreatic intraepithelial neoplasias is important for clinical management. However, morphologic grading of pancreatic intraepithelial neoplasia suffers from significant interobserver variability. A product of cell polarity gene lethal giant larvae 2 is a marker of gastric foveolar epithelium expressed in a basolateral fashion, which is lost or mislocalized in gastric epithelial dysplasia and adenocarcinoma. In this study, we investigated a role of lethal giant larvae 2 expression in differentiating low-grade pancreatic intraepithelial neoplasias, that is, pancreatic intraepithelial neoplasia-1 and pancreatic intraepithelial neoplasia-2, from pancreatic intraepithelial neoplasia-3 and pancreatic ductal adenocarcinoma. The immunohistochemical patterns of lethal giant larvae 2 expression were examined in normal pancreatic ducts, 48 pancreatic intraepithelial neoplasia lesions of all histologic grades, and 91 adenocarcinomas on a tissue microarray or conventional sections. The expression pattern was recorded as basolateral, cytoplasmic, negative, or combinations of any of them. Whereas normal duct epithelia did not exhibit lethal giant larvae immunoreactivity, all but one lesion of low-grade pancreatic intraepithelial neoplasia showed basolateral lethal giant larvae staining. Conversely, all lesions of pancreatic intraepithelial neoplasia-3 and adenocarcinoma showed loss of lethal giant larvae 2 staining and/or its cytoplasmic localization. Interestingly, a basolateral expression was focally seen in 4 adenocarcinomas with a foamy gland pattern and was always admixed with negatively stained areas. In conclusion, our results show that low-grade pancreatic intraepithelial neoplasias express lethal giant larvae 2 in a basolateral fashion recapitulating expression in normal gastric epithelium. Loss or abnormal lethal giant larvae 2 expression is seen in pancreatic intraepithelial neoplasia-3 and adenocarcinoma and might be useful in separating them from lower-grade pancreatic intraepithelial neoplasias.

The epigenetic regulators Bmi1 and Ring1B are differentially regulated in pancreatitis and pancreatic ductal adenocarcinoma

Chronic pancreatitis and pancreatic ductal adenocarcinoma (PDAC) are associated with major changes in cell differentiation. These changes may be at the basis of the increased risk for PDAC among patients with chronic pancreatitis. Polycomb proteins are epigenetic silencers expressed in adult stem cells; up-regulation of Polycomb proteins has been reported to occur in a variety of solid tumours such as colon and breast cancer. We hypothesized that Polycomb might play a role in preneoplastic states in the pancreas and in tumour development/progression. To test these ideas, we determined the expression of PRC1 complex proteins (Bmi1 and Ring1b) during pancreatic development and in pancreatic tissue from mouse models of disease: acute and chronic pancreatic injury, duct ligation, and in K-Ras(G12V) conditional knock-in and caerulein-treated K-Ras(G12V) mice. The study was extended to human pancreatic tissue samples. To obtain mechanistic insights, Bmi1 expression in cells undergoing in vitro exocrine cell metaplasia and the effects of Bmi1 depletion in an acinar cancer cell line were studied. We found that Bmi1 and Ring1B are expressed in pancreatic exocrine precursor cells during early development and in ductal and islet cells-but not acinar cells-in the adult pancreas. Bmi1 expression was induced in acinar cells during acute injury, in acinar-ductal metaplastic lesions, as well as in pancreatic intraepithelial neoplasia (PanIN) and PDAC. In contrast, Ring1B expression was only significantly and persistently up-regulated in high-grade PanINs and in PDAC. Bmi1 knockdown in cultured acinar tumour cells led to changes in the expression of various digestive enzymes. Our results suggest that Bmi1 and Ring1B are modulated in pancreatic diseases and could contribute differently to tumour development.

Pancreatic cancer screening: state of the art

Pancreatic cancer is a devastating disease with a median survival of approximately 6 months after diagnosis. Many factors are associated with a worse outcome; examples include late diagnosis, low resection rate, aggressive tumor behavior and a lack of an effective chemotherapy regimen. Owing to the low prevalence of pancreatic cancer relative to the diagnostic accuracy of present detection methods and the absence of promising treatment modalities, even in early stages, it is currently neither advisable nor cost effective to screen the general population. Efforts are focused on early screening of selected high-risk-cohorts, who account for approximately 10% of patients with pancreatic cancer. These include patients with chronic pancreatitis, individuals with a family history of pancreatic cancer, patients with hereditary pancreatitis, Peutz-Jeghers syndrome, cystic fibrosis or familial atypical multiple mole melanoma. At present, a multimodal-screening approach of endoscopic ultrasound, computed tomography and endoscopic retrograde cholangiopancreatography appears to be the most effective method to screen for pancreatic cancer in high-risk patients. Continued efforts are needed to elucidate effective testing to identify patients with nonhereditary risk factors who will benefit from screening protocols. A combined approach of serum markers, genetic markers and specific imaging studies may prove to be the future of pancreatic screening.