The cell-stretcher: A novel device for the mechanical stimulation of cell populations.

Mechanical stimulation appears to be a critical modulator for many aspects of biology, both of living tissue and cells. The cell-stretcher, a novel device for the mechanical uniaxial stimulation of populations of cells, is described. The system is based on a variable stroke cam-lever-tappet mechanism which allows the delivery of cyclic stimuli with frequencies of up to 10 Hz and deformation between 1% and 20%. The kinematics is presented and a simulation of the dynamics of the system is shown, in order to compute the contact forces in the mechanism. The cells, following cultivation and preparation, are plated on an ad hoc polydimethylsiloxane membrane which is then loaded on the clamps of the cell-stretcher via force-adjustable magnetic couplings. In order to show the viability of the experimentation and biocompatibility of the cell-stretcher, a set of two in vitro tests were performed. Human epithelial carcinoma cell line A431 and Adult Mouse Ventricular Fibroblasts (AMVFs) from a dual reporter mouse were subject to 0.5 Hz, 24 h cyclic stretching at 15% strain, and to 48 h stimulation at 0.5 Hz and 15% strain, respectively. Visual analysis was performed on A431, showing definite morphological changes in the form of cellular extroflections in the direction of stimulation compared to an unstimulated control. A cytometric analysis was performed on the AMVF population. Results show a post-stimulation live-dead ratio deviance of less than 6% compared to control, which proves that the environment created by the cell-stretcher is suitable for in vitro experimentation.

Exploring the elasticity and adhesion behavior of cardiac fibroblasts by atomic force microscopy indentation.

AFM was used to collect the whole force-deformation cell curves. They provide both the elasticity and adhesion behavior of mouse primary cardiac fibroblasts. To confirm the hypothesis that a link exists between the membrane receptors and the cytoskeletal filaments causing therefore changing in both elasticity and adhesion behavior, actin-destabilizing Cytochalsin D was administrated to the fibroblasts. From immunofluorescence observation and AFM loading/unloading curves, cytoskeletal reorganization as well as a change in the elasticity and adhesion was indeed observed. Elasticity of control fibroblasts is three times higher than that for fibroblasts treated with 0.5 µM Cytochalasin. Moreover, AFM loading-unloading curves clearly show the different mechanical behavior of the two different cells analyzed: (i) for control cells the AFM cantilever rises during the dwell time while cells with Cytochalasin fail to show such an active resistance; (ii) the maximum force to deform control cells is quite higher and as far as adhesion is concern (iii) the maximum separation force, detachment area and the detachment process time are much larger for control compared to the Cytochalasin treated cells. Therefore, alterations in the cytoskeleton suggest that a link must exist between the membrane receptors and the cytoskeletal filaments beneath the cellular surface and inhibition of actin polymerization has effects on the whole cell mechanical behavior as well as adhesion.

Acute oral toxicity in mice of a new palytoxin analog: 42-hydroxy-palytoxin.

The acute oral toxicity of a new palytoxin congener, 42-hydroxy-palytoxin (42-OH-PLTX), was investigated in female CD-1 mice. The toxin (300-1697 µg/kg), administered by gavage, induced scratching, jumping, respiratory distress, cyanosis, paralysis and death of mice, with an LD50 of 651 µg/kg (95% confidence limits: 384-1018 µg/kg) within 24 h. Hematoclinical analyses showed increased plasma levels of lactate dehydrogenase and aspartate-aminotransferase at doses of 600 µg/kg and above, as well as of alanine-aminotransferase, creatine phosphokinase and potassium ions at ≥ 848 µg/kg. Histology revealed inflammatory lesions in the non-glandular area of the stomach of mice that survived up to 24 h after gavage (424-1200 µg/kg). Although no histological alterations were seen in skeletal and cardiac muscles, changes in some plasma biomarkers (creatine phosphokinase, lactate dehydrogenase) suggested involvement of these tissues in 42-OH-PLTX oral toxicity, in agreement with epidemiological data on seafood poisonings ascribed to palytoxins. Complete recovery of the tissue and hematological changes was observed two weeks post-exposure. Furthermore, 42-OH-PLTX induced in vitro delayed erythrocyte hemolysis at concentrations similar to those of PLTX (EC50 = 7.6 and 13.2 x 10⁻¹² M, respectively). This hemolysis could be completely neutralized by a monoclonal anti-PLTX antibody. The in vivo data, together with the in vitro data recorded for 42-OH-PLTX, seem to indicate Na+/K+-ATPase as one of the key cellular targets of this toxin.

Case definitions for human poisonings postulated to palytoxins exposure.

A series of case reports and anecdotal references describe the adverse effects on human health ascribed to the marine toxin palytoxin (PLTX) after different exposure routes. They include poisonings after oral intake of contaminated seafood, but also inhalation and cutaneous/systemic exposures after direct contact with aerosolized seawater during Ostreopsis blooms and/or through maintaining aquaria containing cnidarian zoanthids. The symptoms commonly recorded during PLTX intoxication are general malaise and weakness, associated with myalgia, respiratory effects, impairment of the neuromuscular apparatus and abnormalities in cardiac function. Systemic symptoms are often recorded together with local damages whose intensity varies according to the route and length of exposure. Gastrointestinal malaise or respiratory distress is common for oral and inhalational exposure, respectively. In addition, irritant properties of PLTX probably account for the inflammatory reactions typical of cutaneous and inhalational contact. Unfortunately, the toxin identification and/or quantification are often incomplete or missing and cases of poisoning are indirectly ascribed to PLTXs, according only to symptoms, anamnesis and environmental/epidemiological investigations (i.e. zoanthid handling or ingestion of particular seafood). Based on the available literature, we suggest a "case definition of PLTX poisonings" according to the main exposure routes, and, we propose the main symptoms to be checked, as well as, hemato-clinical analysis to be carried out. We also suggest the performance of specific analyses both on biological specimens of patients, as well as, on the contaminated materials responsible for the poisoning. A standardized protocol for data collection could provide a more rapid and reliable diagnosis of palytoxin-poisoning, but also the collection of necessary data for the risk assessment for this family of toxins.

Palytoxin toxicity after acute oral administration in mice.

The acute oral toxicity of palytoxin (PLTX), a highly toxic compound associated with seafood intoxication in tropical and subtropical areas, was investigated in mice. After gavage administration (300-1697 microg/kg) to groups of five female CD-1 mice, signs of toxicity and lethality were recorded for 24 h. The LD(50) was 767 microg/kg (95% confidence limits: 549-1039 microg/kg) and the main symptoms observed were scratching, jumping, respiratory distress and paralysis. Hematoclinical analyses showed increased levels of creatine phosphokinase and lactate dehydrogenase at doses of 600 microg/kg and above, and aspartate transaminase at 848 microg/kg and above. Histological analysis revealed acute inflammation of the forestomach in mice surviving up to 24h after administration (424-1200 microg/kg). Other histological alterations were observed in the liver and pancreas, while cardiac and skeletal muscle cells revealed only ultrastructural alterations visible by transmission electron microscopy. Ultrastructural and hematoclinical findings suggest an involvement of skeletal and/or cardiac muscle as targets of PLTX, according to the observed human symptoms. A NOEL of 300 microg/kg can be estimated from this acute oral toxicity study.

Spontaneous apoptosis and proliferation in human pancreatic cancer.

Several studies have documented the role of programmed cell death in the development and/or progression of cancer. The aims of this study were to analyze (a) the spontaneous apoptosis in human pancreatic duct carcinoma by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-digoxigenin nick end labeling (TUNEL); (b) its correlation with the proliferation rate of the tumor (determined by immunohistochemistry by using monoclonal antibody MIB-1); and (c) the association of apoptotic and mitotic index with the histologic features of the tumor and the outcome of patients. In pancreatic cancer, the apoptotic index (AI) was 4.9 +/- 4.8, and the mitotic index (MI) was 1.3 +/- 1.0 (mean +/- SD). AI was higher in small (<4 cm) than in large (>4 cm) size primary tumors (p = 0.02) and in undifferentiated as compared with differentiated cancers (p = 0.05). Significantly higher values of MI were detected in advanced as compared with early-stage carcinomas (p = 0.03) and when perineural invasion was present (p = 0.03). No correlation was found between AI and MI. Patients with AI > 2.3 survived significantly less than those with lower AI values (p = 0.03). Mitotic index >0.5 was associated with a worse survival (p = 0.006). These results suggest that in pancreatic cancer, spontaneous apoptosis is present and is more evident in small and undifferentiated tumors. Proliferation is increased in the advanced stage of cancer and seems to be independent of apoptosis. Higher levels of apoptosis and proliferation are negative prognostic indexes.

Ki-67 and c-jun expression in pancreatic cancer: a prognostic marker?

The proto-oncogene c-jun is involved in cell proliferation and Ki-67 antigen permits determination of the proportion of proliferating tumour cells. The expression of c-jun and Ki-67 in pancreatic cancer and their relation with tumour histological features and patients survival were evaluated. Specimens were obtained as follows: 14 pancreatic cancer from patients radically operated, 8 liver metastases from subjects submitted to palliation, 5 normal pancreas from organs donors and 5 chronic pancreatitis. Ki-67 and c-jun were studied by immunohistochemistry. The percentage of tumour cells stained for c-jun was increased in 11/14 cases. A high c-jun expression was more frequently found in liver metastases than in pancreatic cancer tissue (p=0.031). The frequency of high c-jun expression was more elevated in short-term as compared to long-term survivors (Fisher's exact test, p=0.031 and log-rank, p=0.03). The percentage of tumour positive cells for Ki-67 showed a mean value of 12.8% in primary pancreatic cancer and was lower than in the liver metastases (32.5%) (p=0.029). Significantly lower values were found in long-term (6.5%) as compared to the short-term survivors (18.1%) (p=0.032 and log-rank, p=0.006). A positive relation was demonstrated with stage (p<0.05), lymph node state (p=0.045) and perineural invasion (p=0.0001). In the multivariate analysis the Ki-67 staining was the most important determinant of long-term survival (p=0.005). c-jun and Ki-67 are overexpressed in pancreatic carcinoma, but only Ki-67 is a strong predictive factor.

The expression of proto-oncogene c-jun in human pancreatic cancer.

The proto-oncogene c-jun is involved in cellular proliferation by interfering with signals that lead to cellular differentiation. Moreover the induction of metalloproteinase gene appears to utilise the c-jun oncogene as intracellular messenger. The aims of this study were to evaluate a) the expression of c-jun oncogene in pancreatic cancer b) its relation with tumor histological features. Surgical specimens of pancreatic cancer were collected from 22 patients radically operated upon, and from 11 submitted to palliation. As a control group, 5 specimens of normal pancreas and 5 specimens of chronic pancreatitis were studied. C-jun staining was graded as follows: (-) positive cells < 10%, (+) from 10 to 30%, (+2), from 30 to 60%, (+3) from 60 to 90%. Glucagon and somatostatin staining was graded counting the positive cells of total numer of Langherans islet cells counted. c-Jun expression (low: < 30% and high: > 30%) was related to stage, architectural and cytological grading, vascular, lymph nodal, perineural invasion. Normal pancreas and chronic pancreatitis tissues appear to express the c-jun protein in less than 10% of ductal cells. The percentage of tumor cells stained for c-jun is increased as compared to the control group in 28/33 cases: in 13 (46%) it ranges from 10 to 30%; in 10 (36%) from 30 to 60% and in 5 (18%) from 60 to 90%. The frequency of high or low c-jun expression is not different in relation to the histological features of tumor. Moreover, c-jun protein is present in 40% of cells of Langherans islets in normal pancreas, chronic pancreatitis and pancreatic cancer. The Langherans islet cells stained for c-jun exhibit also a positivity for glucagon. In conclusion; a) in pancreatic cancer, the expression of c-jun is increased in tumour cells in majority of cases as compared to the control group, b) a c-jun positivity is also found in alpha cells with a pattern not different from control group, but the relation between the alpha cells and c-jun production is unknown, c) c-jun expression does not vary in relation to histological findings.

Serum growth factors in patients with pancreatic cancer.

The aims of this study were (1) to assess possible variations in the serum levels of epidermal growth factor (EGF), insulin-like growth factor I (IGF I) and somatostatin in patients with pancreatic cancer as compared to other pancreatic or extrapancreatic diseases and (2) to ascertain the role of these substances in tumour growth and spread. 35 patients with pancreatic cancer were compared to 15 patients with chronic pancreatitis, 15 with benign hepatobiliary diseases, 23 with benign or malignant gastro-intestinal diseases and 22 control subjects. Increased EGF and IGF I serum levels were found in 10% of patients with pancreatic cancer. Somatostatin levels were increased in 8/16 (50%) patients with pancreatic cancer. No correlation was found between EGF, IGF I or somatostatin and tumour size or stage. In pancreatic cancer somatostatin serum levels were correlated with total bilirubin (p < 0.04), while EGF and IGF I were inversely correlated with fasting serum glucose levels (p < 0.05). In conclusion, (1) the serum levels of EGF, IGF I and somatostatin were not related to tumour size and clinical stage of pancreatic cancer, (2) the serum levels EGF and IGF I may be related to altered glucose metabolism, and (3) liver impairment can influence somatostatin serum levels.

Expression of the protooncogene jun is induced in the rat pancreas by cerulein infusion.

Cholecystokinin (CCK) can stimulate secretion and DNA synthesis in pancreatic acinar cells. Hyperstimulation with cerulein (a CCK analogue) induces acute edematous pancreatitis. To study the effects of in vivo pancreatic stimulation with cerulein, we analyzed the expression of the protooncogenes jun, myc, and fos on the mRNA and protein levels. RNA and protein were extracted from the pancreas of rats administered an infusion of cerulein, 10 micrograms/kg/h (Group A) or 0.25 microgram/kg/h (Group B), or saline (Group C) and sacrificed 2, 4, and 6 h after beginning the infusion and 0, 12, and 24 h and 2, 4, and 6 days after completing the infusion period. Transcript levels were studied using slot-blot analysis. Protein expression was studied using Western blot and immunohistochemistry. No changes were found for the expression of protooncogenes myc and fos on either the transcript or the protein levels. Higher jun mRNA levels were found in Group A than in Group B or C, particularly after 2 h of infusion and 12, 24, and 48 h after the end of a 12-h cerulein infusion. No significant difference was observed in Groups B and C. The jun protein behavior was similar in Groups A and B, revealing two peaks: one early during infusion and a second one after the end of a 12-h cerulein infusion. Jun protein was found mainly in the acinar cells. In conclusion, (1) acinar cells in the rat pancreas respond to cerulein stimulation by increasing the expression of jun; (2) in vivo high doses of cerulein increase the jun mRNA and jun protein levels, whereas low doses raise only the protein levels; and (3) myc and fos are apparently uninfluenced by cerulein administration.

Serum neurotensin in human pancreatic cancer.

The role of neurotensin as a physiologic regulator of exocrine pancreatic secretion is known, but the hormone has only recently been recognized as important mitogen in vitro for human cancer cells. The aim of this study was to evaluate the variations of serum levels of neurotensin in pancreatic cancer. We studied 58 patients: 13 control subjects, 20 pancreatic cancer patients, 11 chronic pancreatitis patients, and 14 cases of extrapancreatic disease. No differences were found between serum values of neurotensin in pancreatic cancer and control subjects or extrapancreatic disease. Significantly higher values were detected in chronic pancreatitis than in pancreatic cancer patients (P < 0.04). In chronic pancreatitis patients, the serum levels of neurotensin were correlated with serum amylase (r = 0.95, P < 0.01). Lower levels of neurotensin were found in stage IV pancreatic cancer than in stages I-II (t = 1.82, P < 0.04) and in grade II than in grade I (t = 2.21, P < 0.02). Significant correlations were found between serum levels of neurotensin and two indices of nutrition: albumin (r = 0.60, P < 0.05) and the percentage reduction in body weight (Z = 2.20, P < 0.02). No correlations were found between serum levels of the hormone and size of the neoplasm or the survival of patients. We can conclude that the serum variations of neurotensin do not seem to be related to the progression of human pancreatic cancer. The variation of serum levels of the hormone may be linked to a poor nutritional status of the patient.

Tumor markers in the diagnosis, monitoring and therapy of pancreatic cancer: state of the art.

The present review focuses on the utility of serum tumor markers in screening, diagnosis, prognosis and monitoring of pancreatic cancer. Serum determination of all tumor markers studied offers no help in screening or early diagnosis of pancreatic cancer. For diagnosis, blood group-related antigens, in particular CA 19-9, are considered the best indicators of this neoplasm. However, as occurs with other glycoproteic tumor markers, the circulating levels of CA 19-9 are significantly influenced by jaundice, probably because its liver metabolism is reduced. Therefore, the finding of elevated CA 19-9 levels in jaundiced patients has to be evaluated with caution. Since pancreatic cancer recurrences are not susceptible to treatment, the clinical role of widespread use of tumor marker determination in follow-up programs is limited and calls for a critical evaluation.

The effect of aging on oro-cecal transit time in normal subjects and patients with gallstone disease.

To ascertain whether aging and/or cholelithiasis can influence oro-cecal transit time (OCTT), we studied a total of 70 subjects, i.e., 10 healthy young adult controls, 22 healthy elderly controls, 18 elderly cholelithiasis patients and 20 elderly subjects with a history of cholecystectomy for gallstones. OCTT was measured by means of the hydrogen breath test after administering a liquid meal of 10 g of lactulose in 200 mL of water, and collecting exhaled breath samples every 10 minutes for 200 minutes. Of all subjects in the group of patients with a history of cholecystectomy, 6/20 were non-hydrogen producers, and therefore were not included in the study. The OCTT was found to be significantly longer in healthy elderly controls, than in healthy young adult controls; the elderly subjects who had undergone cholecystectomy had a longer OCTT than the healthy elderly controls, while no difference was detected when compared to elderly patients with gallstones. In conclusion, OCTT seems to increase in healthy aging. Cholecystectomy also increases OCTT in the elderly, suggesting a link between intestinal motility and the biliary tract which may be of pathophysiological significance.

Is CA242 really a new tumour marker for pancreatic adenocarcinoma?

CA 242, a sialylated carbohydrate epitope situated on the same macromolecule as CA 50 has been proposed as a new tumour marker for pancreatic cancer (PC). The aims of the present study were: (1) to evaluate serum CA 242 versus CA 19-9 in PC patients, and (2) to assess whether these markers can predict tumour spread or patient survival. We studied 59 healthy controls, 27 PC patients, 12 chronic pancreatitis cases, 107 with extra-pancreatic gastrointestinal tumours, 30 with benign jaundice and 24 with benign extra-pancreatic gastrointestinal diseases. Mean CA 242 values were significantly higher in PC than in any other group; CA 19-9 showed a similar pattern. The best diagnostic efficacy (ROC curves analysis) in diagnosing PC was 86% for CA 242 and 84% for CA 19-9, using cut-off values of 60 and 80 U/ml, respectively. In PC, serum levels of both markers were unrelated to tumour spread or size; in PC patients with high levels of CA 242 or CA 19-9 survival was significantly shorter. CA 242 and CA 19-9 were correlated both when considering all the patients together (r = 0.962, p < 0.001) and PC alone (r = 0.880, p < 0.001). Given the very close relationship between CA 242 and CA 19-9, we tested for cross-reactivity between CA 242 antigen and CA 19-9 antibody: CA 242 antigen with CA 19-9 antibody produced a similar curve to CA 242 antigen and its corresponding antibody. In conclusion, CA 242 showed similar diagnostic values to CA 19-9 in assessing PC patients; both seem unrelated to tumour size or spread, but seem to predict survival. Their remarkably similar behaviour is due to cross-reactivity between CA 242 antigen and CA 19-9 antibody, so CA 242 cannot, in our opinion, be considered a new tumour marker for PC.

Insulin-like growth factor-I, interleukin-1 alpha and beta in pancreatic cancer: role in tumor invasiveness and associated diabetes.

We evaluated levels of insulin-like growth factor-I and interleukin-1 alpha and beta in patients with pancreatic cancer; the role of these substances in tumor spread and in hyperglycemia was also investigated. Thirty pancreatic cancer patients (21 with hyperglycemia) were compared with others with diseases causing hyperglycemia [liver cirrhosis (14 cases, 12 with hyperglycemia), chronic pancreatitis (20 cases, 12 with hyperglycemia), type I diabetes mellitus (13 cases, all hyperglycemic)]. Insulin-like growth factor-I was significantly reduced in patients with liver cirrhosis, probably due to a reduced hepatic capacity for synthesis. It was increased in 6 of 30 pancreatic cancer patients; in these subjects it was correlated with alanine aminotransferase and C-peptide, but not with tumor diameter or the presence of metastases. Interleukin-1 alpha and beta were both elevated in pancreatic cancer patients. The former was high, while the latter was low when liver metastases were present. Neither was related to glucose or C-peptide levels. In summary, insulin-like growth factor-I levels are increased in some pancreatic cancer patients but this does not seem to favor tumor spread; however IGF-I could be involved influencing glucose homeostasis. Interleukin-1 alpha increased, while interleukin-1 beta decreased in pancreatic cancer patients with metastases, suggesting a different involvement of these two substances in pancreatic cancer spread.

Diabetes mellitus in pancreatic cancer follow-up.

The aim of this study was to assess the behavior of fasting serum glucose, C-peptide levels and OGTT in pancreatic cancer follow-up. We studied 49 patients with pancreatic cancer (stage I = 8 pts; II = 16 pts; III = 12 pts; IV = 13 pts). At diagnosis 13/49 patients had fasting serum glucose levels of above 140 mg/dL. Of the remaining 36 pts, 22 underwent OGTT, which indicated diabetes mellitus in 9/22 (41%) and impaired glucose tolerance in 7/22 (32%) cases. C-peptide basal values were within the normal range (0.8-2.0 micrograms/L) in 14/49 (28%), above 2.0 micrograms/L in 6/49 (13%) and below 0.8 micrograms/L in 29/49 (59%) of the cases. No significant correlation was found between tumor stage or size and the presence of diabetes or of a reduced glucose tolerance. Twenty-four patients underwent curative resection (group 1) and 16 palliative resection, while the remaining nine did not undergo surgery (group 2). Group 1 and 2 patients had a follow-up of 2 to 40 months (mean = 14 months) and from 1 to 7.5 months (mean = 3.5 months) respectively. In group 1 patients no significant difference was found between pre- and post-operative fasting serum glucose levels. However, in 11/15 (73%) patients who underwent OGTT before and after surgery, an improvement in glucose tolerance was observed after tumor resection. In group 2 patients, a significant increase in fasting serum glucose levels was found during follow-up. In neither of the groups studied were significant variations found in C-peptide levels during the follow-up, although a slight increase was observed in patients who did not undergo surgery. In conclusion, the reduced glucose tolerance or frank diabetes mellitus, which frequently occurs during the onset of pancreatic cancer, does not seem to be related to tumor stage or size. Curative resection ameliorates glucose intolerance, while tumor persistence can enhance serum glucose levels.

Natural history of gallstones in non-insulin-dependent diabetes mellitus. A prospective 5-year follow-up.

This prospective study was undertaken to assess the natural history of gallstones in patients with non-insulin-dependent diabetes. Four hundred forty outpatients with diabetes mellitus were studied; 81 of these had gallstones diagnosed by ultrasound. On the basis of the information they gave, they were divided into two groups: A, asymptomatic; and B, symptomatic (previous episode(s) of biliary pain) at recruitment. Five years after diagnosis, the patients were recalled and questioned about their symptoms. Three of 81 could not be traced and eight had died from diseases not related to gallstones. Seventy were finally evaluated, 47 belonging to group A, 23 to group B. The cumulative percentage of initially asymptomatic patients who presented with biliary pain or complications during the follow-up was 14.9% (4.2% for complications). Of group A patients, 17% underwent cholecystectomy (one prophylactic, six elective and two emergency). One patient (2.1%) died after operation of obstructive jaundice. Of group B patients, 47.8% had biliary symptoms or complications (8.7% cholecystitis); 21.7% were operated (17.4% elective, 4.3% emergency cholecystectomy). Since few patients with asymptomatic gallstones and non-insulin-dependent diabetes mellitus develop pain or complications over time, prophylactic cholecystectomy is probably not advisable.

Beta-cell function in pancreatic adenocarcinoma.

To evaluate beta-cell function in patients with pancreatic cancer, the glucagon stimulation test was performed in seven patients with pancreatic adenocarcinoma, seven patients with type I diabetes mellitus, seven patients with type II diabetes mellitus, and in seven healthy controls. C-peptide serum levels were determined before and after a 1-mg i.v. glucagon injection. Basal C-peptide values were normal or slightly increased in pancreatic cancer and type II diabetic patients and low in type I diabetic patients. Following glucagon stimulation, no significant increase was observed in C-peptide values of type I diabetics and pancreatic cancer patients, whereas significant increases occurred in controls and type II diabetics. It is concluded that the altered beta-cell function found in pancreatic cancer patients may lead to hyperglycemia, which is frequently associated with this tumor type.