Can we screen high-risk individuals to detect early pancreatic carcinoma?

A meta-analysis of the diagnostic value of detecting K-ras mutation in pancreatic juice as a molecular marker for pancreatic cancer

BACKGROUND

K-ras codon 12 mutation is one of the earliest genetic changes in the development of pancreatic cancer (PC) and accurate detection of K-ras mutations is gaining increasing attention in the field of molecular diagnosis.

METHODS

Original research articles which evaluated the diagnostic accuracy of K-ras mutation detection in PC were selected. Data were presented as forest plots and summary receiver operating characteristic curve analysis was used to summarize the overall test performance.

RESULTS

We assessed 16 studies from 15 published articles. The pooled sensitivity and specificity were 59% (95%CI: 54%-64%) and 87% (95%CI: 84%-89%), respectively. The pooled positive likelihood ratio and negative likelihood ratio were 4.13 (95%CI: 2.73-6.25) and 0.42 (95%CI: 0.32-0.56), respectively, and the pooled diagnostic odds ratio was 13.66 (95% CI: 7.25-25.74).

CONCLUSIONS

Our results indicate that the analysis of K-ras mutations in pancreatic juice has a considerable diagnostic value in PC. Further studies with rigorous design, large sample size, and multi-regional co-operation are needed.

The early diagnosis of pancreatic cancer and diabetes: what's the relationship?

Pancreatic cancer (PC) has a dismal prognosis as cancer-specific symptoms occur only at an advanced stage. If the cancer is to be discovered early, it will have to be done in asymptomatic individuals. Since the incidence of PC is low, screening for asymptomatic cancer in the general population will not be feasible. Screening will have to be restricted to subjects at high risk for PC. The proportion of PC patients who also have hyperglycemia or diabetes has previously been under appreciated; new data show that up to 80% are either hyperglycemic or diabetic and this can be evident in the pre-symptomatic phase. Diabetes improves following PC resection suggesting that diabetes is caused by the cancer. Conversely, older subjects with new-onset diabetes have an approximately eight fold higher risk of having PC compared to the general population. Recognition of new-onset diabetes as an early manifestation of PC could lead to diagnosis of asymptomatic, early stage PC. However, primary type 2 diabetes is common and PC is relatively uncommon in the general population and the two forms of diabetes are clinically indistinguishable. The success of the strategy to use new-onset hyperglycemia and diabetes as a screening tool to identify subjects with a high likelihood of having asymptomatic PC will depend largely on our ability to differentiate PC-associated diabetes from the more common type 2 diabetes using a (serologic) biomarker.

Baseline hemoglobin-A1c impacts clinical outcomes in patients with pancreatic cancer

An association between diabetes mellitus and pancreatic ductal adenocarcinoma (PDA) has long been recognized. This article assesses the effect of the baseline hemoglobin-A1c (HbA1c) value on the clinical outcomes of patients with PDA. HbA1c values were prospectively collected on 656 consecutive patients presenting to a pancreas multidisciplinary cancer clinic from 2009 to 2012. Patients were diagnosed with benign pancreatic disease (BPD) or biopsy-confirmed resectable (R), borderline/locally advanced (BL), or metastatic (M) PDA. Excluded were those with prior treatment for PDA or a history of chronic diabetes mellitus (>1-year or unknown duration), resulting in a final cohort of 284 patients. Of 284 patients, 44 had benign disease, 62 had R-PDA, 115 had BL-PDA, and 63 had M-PDA. Patients with malignant disease (R-, BL-, and M-PDA) collectively had a higher average HbA1c value than patients with BPD (6.1% vs 5.6%; P<.001). Among patients with PDA (n=240), HbA1c values of 6.5% or greater were significantly associated with inferior overall survival (OS) compared with patients with HbA1c values less than 6.5% (hazard ratio [HR], 1.74; OS, 10.2 vs 13.0 months; P=.007), along with other known prognostic factors, such as age of 65 years or older, ECOG performance status of 1 or greater, carbohydrate antigen 19-9 level greater than 90, tumor size larger than 3 cm, and disease stage. HbA1c values of 6.5% or greater remained in the final predictive model using backward elimination (HR, 1.46; P=.097), indicating that HbA1c values of 6.5% or greater influence OS of patients with PDA even when accounting for other known prognostic factors. HbA1c level at presentation is significantly higher in patients with PDA than patients with BPD and seems to affect survival.

Factors influencing receptivity to future screening options for pancreatic cancer in those with and without pancreatic cancer family history

Background

Pancreatic cancer (PC) is considered the most lethal cancer and approximately 10% of PC is hereditary. The purpose of the study was to assess attitudes of at-risk family members with two or more relatives affected with pancreas cancer (PC) toward PC risk and future screening options.

Methods

At-risk family members and primary care controls were surveyed regarding perceived PC risk, PC worry/concern, attitude toward cancer screening, screening test accuracy, and intentions regarding PC screening via blood testing or more invasive endoscopic ultrasound (EUS).

Results

PC family members reported greater perceived risk of PC than controls (54% vs. 6%, respectively, p < 0.0001). PC family members also reported higher levels of PC worry/concern than controls (p < 0.0001), although 19% of PC family members indicated they were “not at all concerned” about getting PC. PC family members indicated greater acceptance of a false-negative result on a PC screening test relative to controls (12% vs. 8%, p = 0.02). Both groups reported high (>89%) receptivity to the potential PC screening options presented, though receptivity was greater among PC family members as compared to controls (p < 0.0001) for EUS. In multivariable analyses, degree of PC concern (p < 0.0001) was associated with intention to screen for PC by blood test and EUS, while perceived PC risk was associated with likelihood of undergoing EUS only (p < 0.0001).

Conclusions

Receptivity to screening options for PC appears high. Clinicians should address behavioral and genetic risk factors for PC and foster appropriate concern regarding PC risk among at-risk individuals.

Seven-signal proteomic signature for detection of operable pancreatic ductal adenocarcinoma and their discrimination from autoimmune pancreatitis

There is urgent need for biomarkers that provide early detection of pancreatic ductal adenocarcinoma (PDAC) as well as discrimination of autoimmune pancreatitis, as current clinical approaches are not suitably accurate for precise diagnosis. We used mass spectrometry to analyze protein profiles of more than 300 plasma specimens obtained from PDAC, noncancerous pancreatic diseases including autoimmune pancreatitis patients and healthy subjects. We obtained 1063 proteomic signals from 160 plasma samples in the training cohort. A proteomic signature consisting of 7 mass spectrometry signals was used for construction of a proteomic model for detection of PDAC patients. Using the test cohort, we confirmed that this proteomic model had discrimination power equal to that observed with the training cohort. The overall sensitivity and specificity for detection of cancer patients were 82.6% and 90.9%, respectively. Notably, 62.5% of the stage I and II cases were detected by our proteomic model. We also found that 100% of autoimmune pancreatitis patients were correctly assigned as noncancerous individuals. In the present paper, we developed a proteomic model that was shown able to detect early-stage PDAC patients. In addition, our model appeared capable of discriminating patients with autoimmune pancreatitis from those with PDAC.

Cancers with increasing incidence trends in the United States: 1999 through 2008

Despite declines in incidence rates for the most common cancers, the incidence of several cancers has increased in the past decade, including cancers of the pancreas, liver, thyroid, and kidney and melanoma of the skin, as well as esophageal adenocarcinoma and certain subsites of oropharyngeal cancer associated with human papillomavirus (HPV) infection. Population-based incidence data compiled by the North American Association of Central Cancer Registries were used to examine trends in incidence rates from 1999 through 2008 for the 7 cancers listed by sex, age group, race/ethnicity, and stage at diagnosis. Joinpoint regression was used to calculate average annual percent changes in incidence rates (1999-2008). Rates for HPV-related oropharyngeal cancer, esophageal adenocarcinoma, cancer of the pancreas, and melanoma of the skin increased only in whites, except for esophageal adenocarcinoma, which also increased in Hispanic men. Liver cancer rates increased in white, black, and Hispanic men and in black women only. In contrast, incidence rates for thyroid and kidney cancers increased in all racial/ethnic groups, except American Indian/Alaska Native men. Increases in incidence rates by age were steepest for liver and HPV-related oropharyngeal cancers among those aged 55 [corrected] to 64 years and for melanoma of the skin in those aged 65 years and older. Notably, for HPV-related oropharyngeal cancer in men and thyroid cancer in women, incidence rates were higher in those aged 55 to 64 years than in those aged 65 years and older. Rates increased for both local and advanced stage diseases for most cancer sites. The reasons for these increasing trends are not entirely known. Part of the increase (for esophageal adenocarcinoma and cancers of the pancreas, liver, and kidney) may be linked to the increasing prevalence of obesity as well as increases in early detection practices for some cancers. These rising trends will exacerbate the growing cancer burden associated with population expansion and aging. Additional research is needed to determine the underlying reasons for these increasing trends.

A single nucleotide polymorphism of the cholecystokinin-B receptor predicts risk for pancreatic cancer

There currently are no tests available for early diagnosis or for the identification of patients at risk for development of pancreatic cancer. We report the discovery of single nucleotide polymorphism (SNP) in the cholecystokinin B receptor (CCKBR) gene predicts survival and risk of pancreatic cancer. Growth of human pancreatic cancer is stimulated by gastrin through the CCKBR and an alternatively spliced isoform of the CCKBR gene called CCKCR. One hundred and ten surgically resected benign and malignant pancreatic tissues as well as normal pancreas were prospectively evaluated for CCKBR genotype and protein expression. Analysis demonstrated the expression of the spliced isoform, CCKCR, was associated with a (SNP) (C > A) at position 32 of the intron 4 (IVS 4) of the CCKBR gene. Since the SNP is within an intron, it has not previously been identified in the GWAS studies. Only patients with the A/A or A/C genotypes, exhibited immunoreactivity to a selective CCKCR antibody. Survival among pancreatic cancer patients with the A-SNP was significantly shorter (p = 0.0001, hazard ratio = 3.63) compared with individuals with C/C genotype. Other variables such as surgical margins, lymph node status, histologic grade or adjuvant chemotherapy were not associated with survival. Furthermore, having one or two of the A-alleles was found to increase the risk of pancreatic adenocarcinoma by 174% (p = 0.0192) compared with the C/C wild type. Cancer cells transfected to overexpress the CCKCR demonstrated increased proliferation over controls. Genetic screening for this SNP may aid in early detection of pancreatic cancer in high risk subjects.

Familial pancreatic cancer and hereditary syndromes: screening strategy for high-risk individuals

Globally, and almost evenly across nations, a familial disposition can be found in 4-10% of patients with pancreatic cancer (PC). A family history of PC is a risk for this disease and the risk level changes in correlation with the number of affected relatives. Several hereditary syndromes with potential germline mutation also have a high risk for PC; however, little is yet known regarding the genes responsible for familial pancreatic cancer (FPC). Characteristics of FPC cases are similar to those of other familial tumors, including younger onset than in sporadic cases and an ethnic difference (Ashkenazi Jewish > other Caucasian). Other risks resemble those of sporadic cases and include smoking and diabetes mellitus. People with several genetic syndromes, including Peutz-Jeghers syndrome, hereditary pancreatitis, breast-ovarian cancer syndrome, hereditary nonpolyposis colorectal cancer, and familial adenomatous polyposis also have an increased risk of PC. In many countries, but not yet in Japan, screening of these high-risk individuals is now ongoing for the detection of early PC under established familial pancreatic cancer registries. In addition to the ordinary risk factors, such as smoking, diabetes, pancreatitis, cysts, duct ectasia, and intraductal papillary mucinous neoplasm (IPMN), individuals with a family history of PC and hereditary syndromes are expected to be entered into the screening protocol.

Metabolites of purine nucleoside phosphorylase (NP) in serum have the potential to delineate pancreatic adenocarcinoma

Pancreatic Adenocarcinoma (PDAC), the fourth highest cause of cancer related deaths in the United States, has the most aggressive presentation resulting in a very short median survival time for the affected patients. Early detection of PDAC is confounded by lack of specific markers that has motivated the use of high throughput molecular approaches to delineate potential biomarkers. To pursue identification of a distinct marker, this study profiled the secretory proteome in 16 PDAC, 2 carcinoma in situ (CIS) and 7 benign patients using label-free mass spectrometry coupled to 1D-SDS-PAGE and Strong Cation-Exchange Chromatography (SCX). A total of 431 proteins were detected of which 56 were found to be significantly elevated in PDAC. Included in this differential set were Parkinson disease autosomal recessive, early onset 7 (PARK 7) and Alpha Synuclein (aSyn), both of which are known to be pathognomonic to Parkinson's disease as well as metabolic enzymes like Purine Nucleoside Phosphorylase (NP) which has been exploited as therapeutic target in cancers. Tissue Microarray analysis confirmed higher expression of aSyn and NP in ductal epithelia of pancreatic tumors compared to benign ducts. Furthermore, extent of both aSyn and NP staining positively correlated with tumor stage and perineural invasion while their intensity of staining correlated with the existence of metastatic lesions in the PDAC tissues. From the biomarker perspective, NP protein levels were higher in PDAC sera and furthermore serum levels of its downstream metabolites guanosine and adenosine were able to distinguish PDAC from benign in an unsupervised hierarchical classification model. Overall, this study for the first time describes elevated levels of aSyn in PDAC as well as highlights the potential of evaluating NP protein expression and levels of its downstream metabolites to develop a multiplex panel for non-invasive detection of PDAC.

Reduced plasma level of CXC chemokine ligand 7 in patients with pancreatic cancer

BACKGROUND

Early detection is essential to improve the outcome of patients with pancreatic cancer. A noninvasive and cost-effective diagnostic test using plasma/serum biomarkers would facilitate the detection of pancreatic cancer at the early stage.

METHODS

Using a novel combination of hollow fiber membrane-based low-molecular-weight protein enrichment and LC-MS-based quantitative shotgun proteomics, we compared the plasma proteome between 24 patients with pancreatic cancer and 21 healthy controls (training cohort). An identified biomarker candidate was then subjected to a large blinded independent validation (n = 237, validation cohort) using a high-density reverse-phase protein microarray.

RESULTS

Among a total of 53,009 MS peaks, we identified a peptide derived from CXC chemokine ligand 7 (CXCL7) that was significantly reduced in pancreatic cancer patients, showing an area under curve (AUC) value of 0.84 and a P value of 0.00005 (Mann-Whitney U test). Reduction of the CXCL7 protein was consistently observed in pancreatic cancer patients including those with stage I and II disease in the validation cohort (P < 0.0001). The plasma level of CXCL7 was independent from that of CA19-9 (Pearson's r = 0.289), and combination with CXCL7 significantly improved the AUC value of CA19-9 to 0.961 (P = 0.002).

CONCLUSIONS

We identified a significant decrease of the plasma CXCL7 level in patients with pancreatic cancer, and combination of CA19-9 with CXCL7 improved the discriminatory power of the former for pancreatic cancer.

IMPACT

The present findings may provide a new diagnostic option for pancreatic cancer and facilitate early detection of the disease.

Salivary transcriptomic biomarkers for detection of resectable pancreatic cancer

BACKGROUND & AIMS

Lack of detection technology for early pancreatic cancer invariably leads to a typical clinical presentation of incurable disease at initial diagnosis. New strategies and biomarkers for early detection are sorely needed. In this study, we have conducted a prospective sample collection and retrospective blinded validation to evaluate the performance and translational utilities of salivary transcriptomic biomarkers for the noninvasive detection of resectable pancreatic cancer.

METHODS

The Affymetrix HG U133 Plus 2.0 Array (Affymetrix, Santa Clara, CA) was used to profile transcriptomes and discover altered gene expression in saliva supernatant. Biomarkers discovered from the microarray study were subjected to clinical validation using an independent sample set of 30 pancreatic cancer patients, 30 chronic pancreatitis patients, and 30 healthy controls.

RESULTS

Twelve messenger RNA biomarkers were discovered and validated. The logistic regression model with the combination of 4 messenger RNA biomarkers (KRAS, MBD3L2, ACRV1, and DPM1) could differentiate pancreatic cancer patients from noncancer subjects (chronic pancreatitis and healthy control), yielding a receiver operating characteristic plot, area under the curve value of 0.971 with 90.0% sensitivity and 95.0% specificity.

CONCLUSIONS

The salivary biomarkers possess discriminatory power for the detection of resectable pancreatic cancer, with high specificity and sensitivity. This report provides the proof of concept of salivary biomarkers for the noninvasive detection of a systemic cancer and paves the way for prediction model validation study followed by pivotal clinical validation.

Identification of serum biomarkers for pancreatic adenocarcinoma by proteomic analysis

Diagnosis of pancreatic adenocarcinoma (PaCa) at an early stage is important for successful treatment and improving the prognosis of patients. Serum samples were applied to strong anionic exchange chromatography (SAX) protein chips for protein profiling by surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS) to distinguish PaCa from noncancer. The Wilcoxon rank-sum test, decision tree algorithm, and logistic regression were used to statistically analyze the multiple protein peaks. Sixty-one protein peaks between 2000 and 30,000 m/z ratios were detected to establish multiple decision classification trees for differentiating the known disease states. A sensitivity of 0.833 and a specificity of 1.000 were obtained in distinguishing PaCa from healthy controls and benign pancreatic diseases. Six protein biomarkers related to different PaCa TNM stages were detected (P < 0.01). One protein biomarker (m/z 4016) rich in PaCa had a down-regulated trend when preoperative and postoperative samples (P < 0.05) were compared. Three protein biomarkers (m/z 4155, 4791, and 28,068) were detected in the differential diagnosis of the three test groups (P < 0.05). A peak m/z 28 068 was identified as C14orf16 using ProteinChip immunoassay. C14orf166 levels were significantly higher in the serum of patients with PaCa compared with the control group using a sandwich immunoenzymatic system. Immunolabeling of tissue sections revealed that the C14orf166 protein was strongly expressed in tumor cells. The results suggest that SELDI-TOF-MS serum profiling is helpful for the diagnostic, prognostic or therapeutic effects of PaCa, which is superior to CA 19-9. The identified protein biomarker C14orf166 is a potential biomarker of PaCa.

Detection of pancreatic carcinomas by imaging lactose-binding protein expression in peritumoral pancreas using [18F]fluoroethyl-deoxylactose PET/CT

Background

Early diagnosis of pancreatic carcinoma with highly sensitive diagnostic imaging methods could save lives of many thousands of patients, because early detection increases resectability and survival rates. Current non-invasive diagnostic imaging techniques have inadequate resolution and sensitivity for detection of small size (∼2–3 mm) early pancreatic carcinoma lesions. Therefore, we have assessed the efficacy of positron emission tomography and computer tomography (PET/CT) imaging with β-O-D-galactopyranosyl-(1,4′)-2′-deoxy-2′-[¹⁸F]fluoroethyl-D-glucopyranose ([¹⁸F]FEDL) for detection of less than 3 mm orthotopic xenografts of L3.6pl pancreatic carcinomas in mice. [¹⁸F]FEDL is a novel radioligand of hepatocarcinoma-intestine-pancreas/pancreatitis-associated protein (HIP/PAP), which is overexpressed in peritumoral pancreatic acinar cells.

Methodology/Principal Findings

Dynamic PET/CT imaging demonstrated rapid accumulation of [¹⁸F]FEDL in peritumoral pancreatic tissue (4.04±2.06%ID/g), bi-exponential blood clearance with half-lives of 1.65±0.50 min and 14.14±3.60 min, and rapid elimination from other organs and tissues, predominantly by renal clearance. Using model-independent graphical analysis of dynamic PET data, the average distribution volume ratio (DVR) for [¹⁸F]FEDL in peritumoral pancreatic tissue was estimated as 3.57±0.60 and 0.94±0.72 in sham-operated control pancreas. Comparative analysis of quantitative autoradiographic images and densitometry of immunohistochemically stained and co-registered adjacent tissue sections demonstrated a strong linear correlation between the magnitude of [¹⁸F]FEDL binding and HIP/PAP expression in corresponding regions (r = 0.88). The in situ analysis demonstrated that at least a 2–4 fold apparent lesion size amplification was achieved for submillimeter tumors and to nearly half a murine pancreas for tumors larger than 3 mm.

Conclusion/Significance

We have demonstrated the feasibility of detection of early pancreatic tumors by non-invasive imaging with [¹⁸F]FEDL PET/CT of tumor biomarker HIP/PAP over-expressed in peritumoral pancreatic tissue. Non-invasive non-invasive detection of early pancreatic carcinomas with [¹⁸F]FEDL PET/CT imaging should aid the guidance of biopsies and additional imaging procedures, facilitate the resectability and improve the overall prognosis.

Atypical familial presentation of FAMMM syndrome with a high incidence of pancreatic cancer: case finding of asymptomatic individuals by EUS surveillance

BACKGROUND

Pancreatic cancer (PC) is one of the leading causes of cancer death in Western countries. An increased risk for PC is known in a number of hereditary tumor syndromes. In selected individuals at high risk of developing PC, surveillance of the pancreas might be able to detect premalignant lesions and early invasive cancers, and probably improve survival.

METHODS

In a Dutch family with atypical phenotypic presentation of the familial atypical multiple mole melanoma syndrome with high incidence of PC related to a mutation in the CDKN2A gene, pancreatic surveillance was offered to asymptomatic gene mutation carriers.

RESULTS

Three individuals underwent their first screening with endoscopic ultrasound (EUS) and magnetic resonance imaging at an age of 76, 58, and 51 years. In a mother and a daughter, mass lesions were found by EUS in the tail and body of the pancreas. The smallest lesion was not visualized on subsequent computed tomography and magnetic resonance imaging. After surgical resection histologic examination revealed adenocarcinomas in both cases. The patient with the larger lesion was found to have N1 disease. Side branch intraductal papillary mucinous neoplasias were found in the third patient.

CONCLUSIONS

These findings illustrate the potential of the surveillance of high-risk individuals for PC by EUS. Awareness of clinicians of the existence of hereditary syndromes with increased risk for PC may improve identification of high-risk individuals who could benefit from surveillance. Whether screening improves survival remains to be investigated, as is the optimal interval for screening. Side branch intraductal papillary mucinous neoplasias in these patients may serve as a precancerous marker lesion for early intervention to improve survival.

Prolonged survival in a patient with BRCA2 associated metastatic pancreatic cancer after exposure to camptothecin: a case report and review of literature

Germline mutations in the tumor suppressor genes BRCA1 and BRCA2 have been proven to predict a drastically increased lifetime risk of breast and ovarian cancers in the individuals who carry them. A number of studies have shown that the third most common cancer associated with these mutations is pancreatic cancer. There is evidence of in vivo therapeutic response to the cross-linking agents; such as mitomycin C (MMC) in BRCA2 mutated pancreatic cell lines. We present the 'first patient' who achieved a prolonged survival on irinotecan, a topoisomerase I poison, administered alone and then in combination with cetuximab. Our patient presented at the age of 71 years with a dual diagnosis of prostate carcinoma and pancreatic carcinoma on the background of a significant family history of cancer. On genetic testing, he was found to have the common Ashkenazi Jewish BRCA2 mutation, 6174delT. To date, he has received 22 cycles of docetaxel, capecitabine, and gemcitibine followed by single agent irinotecan every 3 weeks for 27 cycles, and then weekly cetuximab was added to the regimen at cycle 28. His disease then remained stable for an additional 13 months. He did not have mutated KRAS. MMC and oxaliplatin was then introduced upon progression. His current treatment is MMC plus irinotecan as oxaliplatin was removed because of a hypersensitivity reaction. This patient is stable with an Eastern Cooperative Oncology Group performance status of 0, four and a half years (56 months) after his initial diagnosis. DNA topoisomerases are nuclear enzymes responsible for the regulation of DNA topology. They are involved in basic DNA transactions during replication, transcription, and recombination. BRCA2-deficient human cells are deficient in the repair of double-strand breaks and DNA cross-links through homologous recombination. Active poisons of topoisomerase I include derivatives of camptothecin. Our case is the first clinical piece of evidence that demonstrates an increased sensitivity to camptothecin-11 and a reduced topoisomerase I relaxation activity in BRCA2 associated pancreatic cancer. This case shows that patients with metastatic pancreatic carcinoma and BRCA2 mutations may have disease that is biologically more chemosensitive and consequently prolong survival despite prognostically unfavorable disease.

Industrialized MS-based proteomics in the search for circulating biomarkers

Proteomics is the study of the expression, structure and function of proteins under a range of cellular conditions. A rapidly evolving component of this field is clinical proteomics, which focuses on proteins involved in human disease and how they are affected by therapeutic intervention. MS is the main analytical technology for identifying and quantifying proteins whose expression is modulated across the normal to disease continuum. Applying this technology to clinical samples, however, is particularly challenging due to high biological variability in the population, a variety of disease stages, nonuniform response to therapy, multiple concomitant treatments and special requirements for handling samples from clinical trials. Given these challenges, an ‘industrialized’ approach is best suited to clinical biomarker development, with its standard operating procedures, process control and ‘chain of custody’. This review will focus, therefore, on MS-based industrialized proteomics for the discovery and verification of circulating candidate clinical protein biomarkers.

New-onset diabetes: a potential clue to the early diagnosis of pancreatic cancer

Pancreatic cancer has a dismal prognosis because cancer-specific symptoms occur only at an advanced stage. If the cancer is to be discovered early, screening will need to be done in asymptomatic individuals. Because the incidence of pancreatic cancer is low, screening for asymptomatic cancer in the general population is not feasible; therefore, screening will need to be restricted to people at high risk of this disease. The proportion of patients with pancreatic cancer who also have hyperglycaemia or diabetes has previously been under appreciated. New data show that up to 80% of patients are either hyperglycaemic or diabetic, both of which can be detected in the presymptomatic phase. Diabetes has been shown to improve after pancreatic-cancer resection, suggesting that diabetes is caused by the cancer. Conversely, older patients with new-onset diabetes have about an eight-times higher risk of having pancreatic cancer than the general population. Recognition of new-onset diabetes as an early manifestation of pancreatic cancer could lead to the diagnosis of asymptomatic, early-stage pancreatic cancer. However, primary type-2 diabetes is common in the general population and pancreatic cancer is relatively uncommon, and the two forms of diabetes are clinically indistinguishable. The success of a strategy using new-onset hyperglycaemia and diabetes as a screening tool to identify people with a high likelihood of having asymptomatic pancreatic cancer will depend largely on our ability to differentiate pancreatic-cancer-associated diabetes from the more common type-2 diabetes by use of a (serological) biomarker.

New-onset diabetes: a potential clue to the early diagnosis of pancreatic cancer

Pancreatic cancer has a dismal prognosis because cancer-specific symptoms occur only at an advanced stage. If the cancer is to be discovered early, screening will need to be done in asymptomatic individuals. Because the incidence of pancreatic cancer is low, screening for asymptomatic cancer in the general population is not feasible; therefore, screening will need to be restricted to people at high risk of this disease. The proportion of patients with pancreatic cancer who also have hyperglycaemia or diabetes has previously been under appreciated. New data show that up to 80% of patients are either hyperglycaemic or diabetic, both of which can be detected in the presymptomatic phase. Diabetes has been shown to improve after pancreatic-cancer resection, suggesting that diabetes is caused by the cancer. Conversely, older patients with new-onset diabetes have about an eight-times higher risk of having pancreatic cancer than the general population. Recognition of new-onset diabetes as an early manifestation of pancreatic cancer could lead to the diagnosis of asymptomatic, early-stage pancreatic cancer. However, primary type-2 diabetes is common in the general population and pancreatic cancer is relatively uncommon, and the two forms of diabetes are clinically indistinguishable. The success of a strategy using new-onset hyperglycaemia and diabetes as a screening tool to identify people with a high likelihood of having asymptomatic pancreatic cancer will depend largely on our ability to differentiate pancreatic-cancer-associated diabetes from the more common type-2 diabetes by use of a (serological) biomarker.

High histone deacetylase 7 (HDAC7) expression is significantly associated with adenocarcinomas of the pancreas

BACKGROUND

Alterations in HDACs gene expression have been reported in a number of human cancers. No information is available concerning the status of HDACs in pancreatic cancer tumors. The aim of the present study was to evaluate the expression levels of members of class I (HDAC1, 2,, 3), class II (HDAC4, 5, 6, and 7), and class III (SIRT1, 2, 3, 4, 5, and 6) in a set of surgically resected pancreatic tissues.

METHODS

Total RNA was isolated from 11 pancreatic adenocarcinomas (PA): stage 0 (n = 1), IB (n = 1), IIB (n = 6), III (n = 1), IV (n = 2), one serous cystadenoma (SC), one intraductal papillary mucinous tumor of the pancreas (IMPN), one complicating chronic pancreatitis (CP), and normal pancreas (NP) obtained during donor liver transplantation. Moreover, six other control pancreatic were included. HDACs gene expression was conducted using quantitative real-time polymerase chain reaction (qPCR). Protein expression levels were analyzed by Western blot and their localization by immunohistochemistry analyses of cancer tissues sections.

RESULTS

Remarkably, 9 of the 11 PA (approximately 81%) showed significant increase of HDAC7 mRNA levels. In contrast to PA samples, message for HDAC7 was reduced in CP, SC, and IMPN specimens. The Western blot analysis showed increased expression of HDAC7 protein in 9 out of 11 PA samples, in agreement with the qPCR data. Most of the PA tissue sections examined showed intense labeling in the cytoplasm when reacted against antibodies to HDAC7.

CONCLUSION

The data showed alteration of HDACs gene expression in pancreatic cancer. Increased expression of HDAC7 discriminates PA from other pancreatic tumors.

Preoperative serum TA90-IC as an adjunct to serum CA 19-9 in the diagnosis of pancreatic malignancy: a pilot study

PURPOSE

Because TA90, a 90-kDa immunogenic tumor-associated antigen, is expressed by pancreatic cancer cells, we hypothesized that the serum level of its immune complex with IgG (TA90-IC) might be a useful marker for diagnosis of pancreatic malignancy. We also wanted to compare TA90-IC with CA 19-9 in the diagnosis of pancreatic cancer.

METHODS

We undertook a retrospective study of prospectively collected sera from patients with histopathologically proven pancreatic malignancies. Patient sera were analyzed for TA90-IC and CA 19-9. Sera of sex-matched and age-matched healthy volunteers (controls) were analyzed for TA90-IC. The study was conducted at a tertiary medical center. Twenty-one patients with pancreatic malignancies and 29 controls, from whom sera had been obtained and cryopreserved, were included. A positive TA90-IC level was defined as an optical density >/= 0.410 at 405 nm following an enzyme-linked immunosorbent assay based on a murine monoclonal antibody. CA 19-9 levels were determined by immunoradiometric assay performed at outside laboratories (normal range, 0 to 37 U/mL).

RESULTS

Of the 21 patients, 14 had positive TA90-IC levels and 18 had increased CA 19-9 levels (67% vs 86%; p = 0.157). The TA90-IC levels were significantly higher in the cancer group than in the control group (p = 0.0003). Of the 3 patients with normal CA 19-9 levels, 2 had positive TA90-IC levels. The combination of both markers identified 95% of patients with pancreatic malignancy, a significantly higher diagnostic rate than that of either marker alone (p = 0.014). TA90-IC sensitivity was higher for stage II and III disease than for stage IV disease (82% vs 50%).

CONCLUSIONS

TA90-IC assay may improve the prediction of pancreatic malignancy when used in combination with CA 19-9 levels. Because TA90-IC appears to have improved diagnostic accuracy with smaller tumor burden, the role of TA90-IC as an adjunct to CA 19-9 in screening and monitoring progression of early disease warrants further investigation.

Prognostic significance of growth factors and the urokinase-type plasminogen activator system in pancreatic ductal adenocarcinoma

OBJECTIVES

To determine the diagnostic and prognostic significance of growth factors and the urokinase-type plasminogen activator (uPA) system in pancreatic ductal adenocarcinoma (PDAC) using a multigene assay.

METHODS

Messenger RNA (mRNA) expression of 15 genes from epidermal growth factor receptor, insulin-like growth factor (IGF), and uPA families were measured in 46 PDAC tissue samples using quantitative real-time reverse transcription-polymerase chain reaction. These results were compared with those of the uninvolved adjacent (AP) tissue and benign mucinous cystadenomas (BMC). The mRNA expression was evaluated using logistic regression and receiver operating characteristic area under the curve (ROC AUC) analyses. Their relationship with prognosis was tested by Cox regression multivariate analysis.

RESULTS

All genes were overexpressed in most of the PDAC tissue. When compared with AP tissue, the median expression values for IGF-binding protein 3 (IGFBP-3) and uPA receptor (uPAR) was 9.8- and 9.6-fold, respectively. Expression levels of uPA, uPAR, IGF-I, and IGFBP-3 mRNA were significantly greater in PDAC than in BMC. The IGFBP-3 mRNA expression demonstrated greatest ROC AUC values for PDAC versus AP tissue (ROC AUC, 0.745; 95% confidence interval [CI], 0.65-0.86); whereas ROC AUC values were greatest for uPAR when PDAC was compared with BMC (ROC AUC, 0.846; 95% CI, 0.76-0.94). The combination of uPA, uPAR, and IGF-I significantly improved discriminatory power (ROC AUC, 0.965; 95% CI, 0.93-1.00). The IGFBP-3, uPA, plasminogen activator inhibitor-2, and International Union Against Cancer stage had a significant influence on survival, but the effect of IGFBP-3 was lost after multivariate stepwise analysis.

CONCLUSIONS

These results indicate that there is an influence of IGF system in tumor progression from BMC to PDAC, whereas the uPA/uPAR system has the greater influence on survival in PDAC.

Identifying molecular markers for the early detection of pancreatic neoplasia

Pancreatic cancer is the fourth most common cause of cancer death in the United States. There is a great need for better diagnostic markers of pancreatic neoplasia. Better markers would improve the early diagnosis of pancreatic cancer and allow more patients to undergo curative surgical resection. Identifying individuals at high risk of developing pancreatic cancer and applying markers that could identify precancerous lesions of the pancreas in these individuals could allow such lesions to be resected before the development of pancreatic cancer. As we continue to characterize the genetic, epigenetic, and proteomics alterations that occur in pancreatic cancers and their percursors, better diagnostic markers of pancreatic cancer are expected to follow.

MR Imaging of the Pancreas: 1.5T versus 3T

Pancreatic cancer has an almost uniformly grim prognosis. Early detection has the potential to improve survival, however. One promising approach to increase detection rates is the use of MR imaging at 3T. Imaging at 3T improves temporal or spatial resolution for pancreatic evaluation. Known challenges of imaging at 3T, such as increased power deposition and B1 field inhomogeneity, are not significant limitations for pancreatic imaging. Preliminary results suggest that the signal-to-noise ratio can be as much as twice as high as at 1.5T, particularly after contrast administration. Evaluation of the hepatobiliary ducts is comparable or superior to that at 1.5T. Additional studies are needed to determine if the improved image quality translates into improved sensitivity for disease.

Serum proteomic-based analysis of pancreatic carcinoma for the identification of potential cancer biomarkers

To identify new biomarkers that improve the early diagnosis and lead to possible therapeutic targets in pancreatic carcinoma, we performed a proteomic approach to compare serum protein expression patterns of pancreatic carcinoma patients with that of gastric cancer patients, other pancreatic disease patients, and healthy volunteers. By two-dimensional gel electrophoresis (2-DE) analyses and mass spectroscopic identification, 10 protein spots were found significantly changed in pancreatic carcinoma and 5 proteins including cyclin I, Rab GDP dissociation inhibitor beta (GDI2), alpha-1 antitrypsin precursor, Haptoglobin precursor, and Serotransferrin precursor were successfully identified. The increased levels of cyclin I and GDI2 found to be associated with pancreatic carcinoma were further confirmed by Western blot analyses in an independent series of serum samples and/or pancreatic juice samples. Applying immunohistochemistry, we further validated expression of cyclin I and GDI2 in additional pancreatic carcinomas. These results indicate that cyclin I and GDI2 may be potential molecular targets for pancreatic cancer diagnostics and therapeutics.

The role of epigenetic alterations in pancreatic cancer

The past several years have witnessed an explosive increase in our knowledge about epigenetic features in human cancers. It has become apparent that pancreatic cancer is an epigenetic disease, as it is a genetic disease, characterized by widespread and profound alterations in DNA methylation. The introduction of genome-wide screening techniques has accelerated the discovery of a growing list of genes with abnormal methylation patterns in pancreatic cancer, and some of these epigenetic events play a role in the neoplastic process. The detection and quantification of DNA methylation alterations in pancreatic juice is likely a promising tool for the diagnosis of pancreatic cancer. The potential reversibility of epigenetic changes in genes involved in tumor progression makes them attractive therapeutic targets, but the efficacy of epigenetic therapies in pancreatic cancer, such as the use of DNA methylation inhibitors, remains undetermined. In this review, we briefly summarize recent research findings in the field of pancreatic cancer epigenetics and discuss their biological and clinical implications.

The inherited genetics of pancreatic cancer and prospects for secondary screening

It is estimated that pancreatic cancer has a familial component in approximately 5-10% of cases. Some of these cases are part of a defined cancer syndrome with a known gene mutation but in the remaining the causative gene remains unknown. In recent years, a better understanding of the molecular events that occur in the progression model of pancreatic cancer has lead to the development of secondary screening programmes with the aim of identifying early precursor lesions or pre-invasive cancer at a stage amenable to curative resection. High-risk groups who have an inherited predisposition for pancreatic cancer form the ideal group to study in developing a robust screening programme. Multimodality screening using computed tomography and endoluminal ultrasound in combination with molecular analysis of pancreatic juice are proving promising as diagnostics tools or at least serving as predictors of risk over a defined period.

Possible detection of pancreatic cancer by plasma protein profiling

The survival rate of pancreatic cancer patients is the lowest among those with common solid tumors, and early detection is one of the most feasible means of improving outcomes. We compared plasma proteomes between pancreatic cancer patients and sex- and age-matched healthy controls using surface-enhanced laser desorption/ionization coupled with hybrid quadrupole time-of-flight mass spectrometry. Proteomic spectra were generated from a total of 245 plasma samples obtained from two institutes. A discriminating proteomic pattern was extracted from a training cohort (71 pancreatic cancer patients and 71 healthy controls) using a support vector machine learning algorithm and was applied to two validation cohorts. We recognized a set of four mass peaks at 8,766, 17,272, 28,080, and 14,779 m/z, whose mean intensities differed significantly (Mann-Whitney U test, P < 0.01), as most accurately discriminating cancer patients from healthy controls in the training cohort [sensitivity of 97.2% (69 of 71), specificity of 94.4% (67 of 71), and area under the curve value of 0.978]. This set discriminated cancer patients in the first validation cohort with a sensitivity of 90.9% (30 of 33) and a specificity of 91.1% (41 of 45), and its discriminating capacity was further validated in an independent cohort at a second institution. When combined with CA19-9, 100% (29 of 29 patients) of pancreatic cancers, including early-stage (stages I and II) tumors, were detected. Although a multi-institutional large-scale study will be necessary to confirm clinical significance, the biomarker set identified in this study may be applicable to using plasma samples to diagnose pancreatic cancer.

Biomarker discovery from pancreatic cancer secretome using a differential proteomic approach

Quantitative proteomics can be used as a screening tool for identification of differentially expressed proteins as potential biomarkers for cancers. Candidate biomarkers from such studies can subsequently be tested using other techniques for use in early detection of cancers. Here we demonstrate the use of stable isotope labeling with amino acids in cell culture (SILAC) method to compare the secreted proteins (secretome) from pancreatic cancer-derived cells with that from non-neoplastic pancreatic ductal cells. We identified 145 differentially secreted proteins (>1.5-fold change), several of which were previously reported as either up-regulated (e.g. cathepsin D, macrophage colony stimulation factor, and fibronectin receptor) or down-regulated (e.g. profilin 1 and IGFBP-7) proteins in pancreatic cancer, confirming the validity of our approach. In addition, we identified several proteins that have not been correlated previously with pancreatic cancer including perlecan (HSPG2), CD9 antigen, fibronectin receptor (integrin beta1), and a novel cytokine designated as predicted osteoblast protein (FAM3C). The differential expression of a subset of these novel proteins was validated by Western blot analysis. In addition, overexpression of several proteins not described previously to be elevated in human pancreatic cancer (CD9, perlecan, SDF4, apoE, and fibronectin receptor) was confirmed by immunohistochemical labeling using pancreatic cancer tissue microarrays suggesting that these could be further pursued as potential biomarkers. Lastly the protein expression data from SILAC were compared with mRNA expression data obtained using gene expression microarrays for the two cell lines (Panc1 and human pancreatic duct epithelial), and a correlation coefficient (r) of 0.28 was obtained, confirming previously reported poor associations between RNA and protein expression studies.

Probability of pancreatic cancer following diabetes: a population-based study

BACKGROUND & AIMS

Although diabetes occurs frequently in pancreatic cancer, the value of new-onset diabetes as a marker of underlying pancreatic cancer is unknown.

METHODS

We assembled a population-based cohort of 2122 Rochester, Minnesota, residents age > or =50 years who first met standardized criteria for diabetes between January 1, 1950, and December 31, 1994, and identified those who developed pancreatic cancer within 3 years of meeting criteria for diabetes. We compared observed rates of pancreatic cancer with expected rates based on the Iowa Surveillance Epidemiology and End Results registry. In a nested case control study, we compared body mass index (BMI) and smoking status in diabetes subjects with and without pancreatic cancer.

RESULTS

Of 2122 diabetic subjects, 18 (0.85%) were diagnosed with pancreatic cancer within 3 years of meeting criteria for diabetes; 10 of 18 (56%) were diagnosed <6 months after first meeting criteria for diabetes, and 3 were resected. The observed-to-expected ratio of pancreatic cancer in the cohort was 7.94 (95% CI, 4.70-12.55). Compared with subjects without pancreatic cancer, diabetic subjects with pancreatic cancer were more likely to have met diabetes criteria after age 69 (OR = 4.52, 95% CI, 1.61-12.74) years but did not differ significantly with respect to BMI values (29.2 +/- 6.8 vs 26.5 +/- 5.0, respectively). A larger proportion of those who developed pancreatic cancer were ever smokers (92% vs 69%, respectively), but this did not reach statistical significance.

CONCLUSIONS

Approximately 1% of diabetes subjects aged > or =50 years will be diagnosed with pancreatic cancer within 3 years of first meeting criteria for diabetes. The usefulness of new-onset diabetes as marker of early pancreatic cancer needs further evaluation.

Molecular Markers of Early Pancreatic Cancer

Pancreatic cancer is a deadly disease and the fourth most common cause of cancer death in the United States. Since chemotherapy and radiotherapy have thus far largely failed to significantly improve the survival of patients with pancreatic ductal adenocarcinoma, there is considerable interest in identifying better diagnostic markers of pancreatic neoplasia. Not only could better markers improve the early diagnosis of pancreatic cancer and allow more patients to undergo curative surgical resection, but also could potentially be used for patients at high risk of developing pancreatic cancer to identify precancerous lesions while they are amenable to cure. A wealth of information has recently become available about gene expression, DNA methylation, and proteomics alterations that occur in pancreatic cancers creating hope that better diagnostic markers of pancreatic cancer will be soon forthcoming.

Screening for pancreatic neoplasia in high-risk individuals: who, what, when, how?

Pancreatic cancer (PC) is a highly lethal disease. Most symptomatic, clinically detected PCs are advanced and not curable. Indeed, the estimated 5-year survival rate is 4%, which is attributable to late diagnosis and low resection rate. Screening of high-risk individuals and early detection of small PCs and precursor lesions might improve the outcome if curative therapy could be offered in the presymptomatic stage. This article summarizes the available published data and preliminary results and discusses the different approaches to screening for pancreatic neoplasia at 2 university-based programs in the United States.

Prediction of pancreatic cancer by serum biomarkers using surface-enhanced laser desorption/ionization-based decision tree classification

OBJECTIVE

In order to improve the prognosis of pancreatic cancer patients, it is crucial to explore novel tools for its early diagnosis. Here, we attempted to screen serum biomarkers to distinguish pancreatic cancer from non-cancer individuals.

METHODS

47 serum samples from pancreatic cancer patients, 39 of whom had small surgically resectable cancers, were collected before surgery, and an additional 53 serum samples from age- and sex-matched individuals without cancer were used as controls. The surface-enhanced laser desorption/ionization (SELDI) ProteinChip was applied to analyze serum protein profiling. 54 samples (27 with pancreatic cancer and 27 controls) were analyzed in the training set by a decision tree algorithm to be able to separate pancreatic cancer from controls. A double-blind test was used to determine the sensitivity and specificity of the classification model.

RESULTS

A panel of six biomarkers was selected to set up a decision tree as the classification model. The model separated effectively pancreatic cancer from control samples, achieving a sensitivity of 88.9% and a specificity of 74.1%. The double-blind test challenged the model with a sensitivity of 80% and a specificity of 84.6%.

CONCLUSION

The SELDI ProteinChip combined with an artificial intelligence classification algorithm shows great potential for the diagnosis of pancreatic cancer.

Alterations of the tissue inhibitor of metalloproteinase-3 (TIMP3) gene in pancreatic adenocarcinomas

OBJECTIVES

Tissue inhibitor of metalloproteinase-3 (TIMP3) antagonizes matrix metalloproteinase activity and can suppress tumor growth, angiogenesis, invasion, and metastases. In the present study, the involvement of TIMP3 in the tumorigenesis of 34 pancreatic adenocarcinomas was evaluated.

METHODS

Immunohistochemistry, methylation-specific PCR, and RNA expression analysis (RT-PCR) of TIMP3 were performed in 34 resected and microdissected primary pancreatic adenocarcinomas.

RESULTS

Immunohistochemistry showed loss or strongly reduced protein expression in 17 of 34 pancreatic adenocarcinomas (50%) that corresponded to loss of TIMP3-RNA-expression. Promoter hypermethylation was identified in 2 of 34 tumors (6%). It was tumor specific and corresponded to a loss of TIMP3 protein expression. TIMP3 alterations did not correlate with any clinical feature such as tumor size or survival.

CONCLUSION

TIMP3 seems to play an important role in the tumorigenesis of primary pancreatic adenocarcinomas. In contrast to other tumors, hypermethylation seems not to be the key mechanism for the inactivation of TIMP3. Other methods of gene inactivation need to be identified.

Serum diagnosis of pancreatic adenocarcinoma using surface-enhanced laser desorption and ionization mass spectrometry

PURPOSE

Each year in the United States, approximately 30,000 people die from pancreatic cancer. Fewer than 5% of patients survive >5 years after diagnosis, because most patients present with advanced disease. Early diagnosis may improve the prognosis of patients with pancreatic cancer.

EXPERIMENTAL DESIGN

In an attempt to improve on current approaches to the serological diagnosis of pancreatic cancer, we analyzed serum samples from patients with and without pancreatic cancer using surface-enhanced laser desorption and ionization (SELDI) protein chip mass spectrometry. Using a case-control study design, serum samples from 60 patients with resectable pancreatic adenocarcinoma were compared with samples from 60 age- and sex-matched patients with nonmalignant pancreatic diseases, as well as 60 age- and sex-matched healthy controls. To increase the number of proteins potentially identifiable, serum was fractionated using anion exchange and profiled on two ProteinChip surfaces (metal affinity capture and weak cation exchange).

RESULTS

We determined a minimum set of protein peaks able to discriminate between patient groups and used the unified maximum separability algorithm to compare the performance of the individual marker panels alone or in conjunction with CA19-9. Among the peaks identified by SELDI profiling that had the ability to distinguish between patient groups, the 2 most discriminating protein peaks could differentiate patients with pancreatic cancer from healthy controls with a sensitivity of 78% and specificity of 97%. These 2 markers performed significantly better than the current standard serum marker, CA19-9 (P < 0.05). The diagnostic accuracy of the 2 markers was improved by using them in combination with CA 19-9. Similarly, a combination of 3 SELDI markers and CA19-9 was superior to CA19-9 alone in distinguishing individuals with pancreatic cancer from the combined pancreatic disease controls and healthy subject groups (P = 0.078). SELDI markers were also better than CA19-9 in distinguishing patients with pancreatic cancer from those with pancreatitis.

CONCLUSION

SELDI profiling of serum can be used to accurately differentiate patients with pancreatic cancer from those with other pancreatic diseases and from healthy controls.

Time interval between abnormalities seen on CT and the clinical diagnosis of pancreatic cancer: retrospective review of CT scans obtained before diagnosis

OBJECTIVE

Our purpose was to determine whether abdominal CT can detect pancreatic cancer before its clinical diagnosis.

SUBJECTS AND METHODS

Two radiologists interpreted in a blinded manner 62 CT scans in 28 pancreatic cancer patients that were obtained before histologic diagnosis and 89 CT scans in 89 control subjects and noted specific CT findings. The presence of pancreatic cancer was characterized as definite, suspicious, low probability, or normal. The scans of the pancreatic cancer patients were divided into four groups on the basis of the time interval preceding cancer diagnosis (0-2, 2-6, 6-18, or > 18 months), and one scan (closest to 18 months) was selected per patient per time interval. Sensitivity and specificity for pancreatic cancer and interobserver agreement for CT findings were calculated.

RESULTS

Radiologists agreed that CT findings definite or suspicious for pancreatic cancer were present in 50% of the scans obtained 2-6 and 6-18 months before the diagnosis of pancreatic cancer (3/6 and 4/8 scans, respectively), but they noted such CT findings in only 7% (1/15) of the scans obtained more than 18 months before diagnosis. Pancreatic duct dilatation and cutoff were early CT findings identified by both radiologists and were associated with near-perfect and substantial interobserver agreement (kappa = 0.84 and 0.76, respectively). Ninety-five percent confidence intervals of specificity for tumor absence ranged from 92% to 100%.

CONCLUSION

CT can detect a significant proportion of asymptomatic incident pancreatic cancers before the clinical diagnosis of pancreatic cancer. CT should be considered in screening at-risk patient populations. Pancreatic duct dilatation and cutoff are early findings associated with the development of pancreatic cancer and can be detected on CT with a high degree of reproducibility.

Management of Patients at High Risk for Pancreatic Cancer

Because pancreatic cancer patients seldom exhibit disease-specific symptoms until the cancer is at an advanced stage, its diagnosis is a virtual death sentence. Therefore, to make a significant impact on long-term survival for subjects with pancreatic cancer, asymptomatic individuals would have to be screened for premalignant precursors of pancreatic cancer or for asymptomatic pancreatic cancer. A number of formidable obstacles limit the ability of healthcare providers to screen for early neoplastic changes and to make a very early and specific diagnosis of pancreatic cancer. These include lack of a high-risk population for sporadic pancreatic cancer and lack of a simple, noninvasive test sensitive enough to detect small cancers. However, progress is being made in defining various high-risk groups for pancreatic cancer, and improvements in imaging modalities make detection of premalignant lesions and small cancers possible in such individuals. The protocols currently being studied, including use of endoscopic ultrasound and endoscopic retrograde cholangiopancreatography to detect precancerous lesions and small pancreatic cancer in high-risk patients, are still in the research arena and not yet ready for clinical practice.

SPARC/osteonectin is a frequent target for aberrant methylation in pancreatic adenocarcinoma and a mediator of tumor-stromal interactions

Deregulated expression of SPARC/osteonectin, a secreted glycoprotein with multiple biological functions, has been associated with the progression of various cancers. Using microarrays, we previously identified SPARC as one of the genes induced by treatment with a DNA methylation inhibitor in pancreatic cancer cells. We therefore analysed the expression pattern and methylation status of the SPARC gene in pancreatic cancer. Gene expression profiling by oligonucleotide microarray and reverse transcription-PCR analyses demonstrated that SPARC mRNA was expressed in non-neoplastic pancreatic ductal epithelial cells, but was not expressed in a majority of pancreatic cancer cell lines. The loss of SPARC expression was associated with aberrant hypermethylation of its CpG island. Immunohistochemical labeling revealed that the SPARC protein was overexpressed in the stromal fibroblasts immediately adjacent to the neoplastic epithelium in primary pancreatic cancers, but rarely expressed in the cancers themselves. Primary fibroblasts derived from pancreatic cancer strongly expressed SPARC mRNA and secreted SPARC protein into the conditioned media, and treatment of pancreatic cancer cells with exogenous SPARC resulted in growth suppression. SPARC expression in fibroblasts from noncancerous pancreatic tissue was augmented by coculture with pancreatic cancer cells. These findings suggest that SPARC is a frequent target for aberrant methylation in pancreatic cancer and that SPARC expression in fibroblasts adjacent to pancreatic cancer cells is regulated through tumor-stromal interactions.

Timing and extent of surgical intervention in patients from hereditary pancreatic cancer kindreds

Our knowledge of the molecular and genetic etiology of hereditary pancreatic cancer has expanded considerably and is steadily increasing. However, there are only a few hard data available regarding the clinical and surgical management of these patients. Surgery is currently performed when we detect dysplastic changes in the pancreas or when cancer is suspected. Of the available diagnostic modalities, endoscopic ultrasonography has proven so far to be the most useful for detecting dysplastic changes in the pancreases of patients from hereditary pancreatic cancer kindreds. It seems reasonable, once dysplasia has been diagnosed in a high-risk patient, to proceed to total pancreatectomy. The multifocal nature of dysplastic lesions precludes any type of operation that would leave behind pancreatic tissue. Currently, prophylactic whole-organ resection in the absence of premalignant lesions cannot be recommended since we do not know the exact risk for the development of cancer.